SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME

Abstract

According to one embodiment, a semiconductor device includes a first electrode, a second electrode, a third electrode, a first semiconductor region, and a second semiconductor region. The first to third electrodes extend in the first direction. A second direction from the first electrode to the second electrode is perpendicular to the first direction. The first semiconductor region includes Alx1Ga1−x1N (0≤x1<1). The first semiconductor region includes first to fifth partial regions. A third direction from the first partial region to the first electrode crosses a plane including the first and second directions. A direction from the second partial region to the second electrode, and a direction from the third partial region to the third electrode are along the third direction. The second semiconductor region includes Alx2Ga1−x2N (0

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2023-083719, filed on May 22, 2023; the entire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein generally relate to a semiconductor device and a method for manufacturing the same device.

BACKGROUND

For example, in semiconductor devices, improvement in characteristics is desired.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plan view illustrating a semiconductor device according to a first embodiment;

FIG. 2 is a schematic cross-sectional view illustrating the semiconductor device according to the first embodiment;

FIG. 3 is a schematic cross-sectional view illustrating a part of the semiconductor device according to the first embodiment;

FIG. 4 is a schematic cross-sectional view illustrating a part of a semiconductor device according to the first embodiment;

FIG. 5 is a schematic cross-sectional view illustrating a part of a semiconductor device according to the first embodiment;

FIG. 6 is a schematic cross-sectional view illustrating a part of a semiconductor device according to the first embodiment;

FIG. 7 is a schematic cross-sectional view illustrating a part of a semiconductor device according to the first embodiment;

FIG. 8 is a schematic cross-sectional view illustrating a part of a semiconductor device according to the first embodiment;

FIG. 9 is a schematic cross-sectional view illustrating a semiconductor device according to the first embodiment;

FIG. 10 is a schematic cross-sectional view illustrating a semiconductor device according to the first embodiment;

FIGS. 11A and 11B are schematic cross-sectional views illustrating a method for manufacturing a semiconductor device according to a second embodiment; and

FIGS. 12A and 12B are schematic cross-sectional views illustrating a method for manufacturing a semiconductor device according to the second embodiment.

DETAILED DESCRIPTION

According to one embodiment, a semiconductor device includes a first electrode, a second electrode, a third electrode, a first semiconductor region, and a second semiconductor region. The first electrode extends in a first direction. The second electrode extends in the first direction. A second direction from the first electrode to the second electrode is perpendicular to the first direction. The third electrode extends in the first direction. A position of the third electrode in the second direction is between a position of the first electrode in the second direction and a position of the second electrode in the second direction. The first semiconductor region includes Al_x1Ga_1−x1N (0≤x1<1). The first semiconductor region includes a first partial region, a second partial region, a third partial region, a fourth partial region, and a fifth partial region. A third direction from the first partial region to the first electrode crosses a plane including the first direction and the second direction. A direction from the second partial region to the second electrode is along the third direction. A direction from the third partial region to the third electrode is along the third direction. A position of the fourth partial region in the second direction is between a position of the first partial region in the second direction and a position of the third partial region in the second direction. A position of the fifth partial region in the second direction is between the position of the third partial region in the second direction and a position of the second partial region in the second direction. The second semiconductor region includes Al_x2Ga_1−x2N (0<x2<1, x1<x2). The second semiconductor region includes a first semiconductor portion and a second semiconductor portion. A direction from the fourth partial region to the first semiconductor portion is along the third direction. A direction from the fifth partial region to the second semiconductor portion is along the third direction. The second semiconductor portion includes a first region and a second region. A position of the first region in the second direction is between a position of the second region in the second direction and the position of the second electrode in the second direction. A concentration of fluorine in the first region is higher than a concentration of fluorine in the second region. Or, the first region includes fluorine and the second region does not include fluorine.

Various embodiments are described below with reference to the accompanying drawings.

The drawings are schematic and conceptual; and the relationships between the thickness and width of portions, the proportions of sizes among portions, etc., are not necessarily the same as the actual values. The dimensions and proportions may be illustrated differently among drawings, even for identical portions.

In the specification and drawings, components similar to those described previously in an antecedent drawing are marked with like reference numerals, and a detailed description is omitted as appropriate.

First Embodiment

FIG. 1 is a schematic plan view illustrating semiconductor device according to a first embodiment.

FIG. 2 is a schematic cross-sectional view illustrating the semiconductor device according to the first embodiment.

FIG. 2 is a cross-sectional view taken along the line A1-A2 of FIG. 1.

As shown in FIGS. 1 and 2, a semiconductor device 110 according to the embodiment includes a first electrode 51, a second electrode 52, a third electrode 53, a first semiconductor region 10 and a second semiconductor region 20.

As shown in FIG. 1, the first electrode 51, the second electrode 52, and the third electrode 53 extend in a first direction D1. A second direction D2 from the first electrode 51 to the second electrode 52 is perpendicular to the first direction D1.

The first direction D1 is a Y-axis direction. One direction perpendicular to the Y-axis direction is defined as an X-axis direction. A direction perpendicular to the Y-axis direction and the X-axis direction is defined as a Z-axis direction. For example, the second direction D2 is the X-axis direction.

A length of the first electrode 51 in the first direction D1 is longer than a length (width) of the first electrode 51 in the second direction D2. A length of the second electrode 52 in the first direction D1 is longer than a length (width) of the second electrode 52 in the second direction D2. A length of the third electrode 53 in the first direction D1 is longer than a length (width) of the third electrode 53 in the second direction D2. The first electrode 51, the second electrode 52 and the third electrode 53 are stripes extending in the first direction.

A position of the third electrode 53 in the second direction D2 is between a position of the first electrode 51 in the second direction D2 and a position of the second electrode 52 in the second direction D2.

The first semiconductor region 10 includes Al_x1Ga_1−x1N (0≤x1<1). The composition ratio x1 is, for example, not less than 0 and not more than 0.1. The first semiconductor region 10 is, for example, a GaN layer.

As shown in FIG. 2, the first semiconductor region 10 includes a first partial region 11, a second partial region 12, a third partial region 13, a fourth partial region 14 and a fifth partial region 15. A third direction D3 from the first partial region 11 to the first electrode 51 crosses a plane including the first direction D1 and the second direction D2. The third direction D3 is, for example, the Z-axis direction. 5 A direction from the second partial region 12 to the second electrode 52 is along the third direction D3. A direction from the third partial region 13 to the third electrode 53 is along the third direction D3. The first partial region 11 overlaps the first electrode 51 in the third direction D3. The second partial region 1012 overlaps the second electrode 52 in the third direction D3. The third partial region 13 overlaps the third electrode 53 in the third direction D3.

A position of the fourth partial region 14 in the second direction D2 is between a position of the first partial region 11 in the second direction D2 and a position of the third partial region 13 in the second direction D2. A position of the fifth partial region 15 in the second direction D2 is between a position of the third partial region 13 in the second direction D2 and a position of the second partial region 12 in the second direction D2.

The second semiconductor region 20 includes Al_x2Ga_1−x2N (0<x2<1, x1<x2). The composition ratio x2 is, for example, not less than 0.2 and not more than 0.35. The second semiconductor region 20 is, for example, an AlGaN layer. The second semiconductor region 20 includes a first semiconductor portion 21 and a second semiconductor portion 22. A direction from the fourth partial region 14 to the first semiconductor portion 21 is along the third direction D3. A direction from the fifth partial region 15 to the second semiconductor portion 22 is along the third direction D3.

The second semiconductor portion 22 includes a first region 22a and a second region 22b. A position of the first region 22a in the second direction D2 is between a position of the second region 22b in the second direction D2 and a position of the second electrode 52 in the second direction D2. A concentration of fluorine in the first region 22a is higher than a concentration of fluorine in the second region 22b. Alternatively, the first region 22a includes fluorine and the second region 22b does not include fluorine.

For example, a current flowing between the first electrode 51 and the second electrode 52 can be controlled by a potential of the third electrode 53. The potential of the third electrode 53 may be based on a potential of the first electrode 51. For example, the first electrode 51 functions as a source electrode. For example, the second electrode 52 functions as a drain electrode. For example, the third electrode 53 functions as a gate electrode. The semiconductor device 110 is, for example, a transistor.

As shown in FIG. 2, the first semiconductor region 10 includes a portion facing the second semiconductor region 20. A carrier region 10c is formed in this portion. The carrier region 10c is, for example, a two-dimensional electron gas. The semiconductor device 110 is, for example, a HEMT (High Electron Mobility Transistor).

For example, the distance between the first electrode 51 and the third electrode 53 in the second direction D2 is shorter than the distance between the third electrode 53 and the second electrode 52 in the second direction D2. More stable characteristics can be obtained.

In the embodiments, a voltage applied to the second electrode 52 is higher than a voltage applied to the third electrode 53. Therefore, a high electric field is concentrated in a region near the second electrode 52, and the operation tends to become unstable. For example, traps are likely to be generated due to the high electric field generated at the end of the second electrode 52. This makes it easier for the characteristics to change, for example. For example, current collapse may occur.

In the embodiment, as described above, the first region 22a close to the second electrode 52 include fluorine. For example, when fluorine is present in the first region 22a, the generation of traps is suppressed. This makes it easier to maintain stable characteristics even when a high electric field is concentrated in a region close to the second electrode 52. For example, current collapse is suppressed. According to the embodiment, a semiconductor device with improved characteristics can be provided.

In the embodiments, the second region 22b having a low concentration of fluorine or including no fluorine is provided. For example, it is easier to maintain a lower on-resistance than when all of the second semiconductor portion 22 between the third electrode 53 and the second electrode 52 includes fluorine. According to the embodiment, for example, stable characteristics and low on-resistance can be obtained.

In one example according to the embodiment, the concentration of fluorine in the first region 22a is not less than 1×10¹⁶ cm⁻³ and not more than 1×10¹⁸ cm⁻³. Traps can be suppressed more stably. On the other hand, the concentration of fluorine in the second region 22b is less than 1×10¹⁶ cm⁻³. Low on-resistance is stable and easy to obtain.

In one example, the first region 22a and the second region 22b having different concentrations of fluorine are obtained by selectively introducing fluorine into the second semiconductor region 20 using a mask, or the like.

FIG. 3 is a schematic cross-sectional view illustrating a part of the semiconductor device according to the first embodiment.

FIG. 3 shows an enlarged example of a part of the semiconductor device 110 that includes the second electrode 52.

As shown in FIG. 3, the second electrode 52 includes a first electrode portion 52a and a second electrode portion 52b. A direction from the first region 22a to at least a part of the first electrode portion 52a is along the second direction D2. At least a part of the first region 22a is located between the first semiconductor region 10 and the second electrode portion 52b in the third direction D3. The first electrode portion 52a is electrically connected to the second partial region 12 (and the second semiconductor portion 22).

For example, the second electrode portion 52b is an eaves portion. The second electrode portion 52b may function as a field plate on the drain side. A high electric field tends to occur locally at the end of the second electrode portion 52b. By providing the first region 22a including fluorine under the second electrode portion 52b, the characteristics become more stable.

In FIG. 3, a region 10F surrounded by a broken line includes fluorine. At least a part of the first region 22a is included in the region 10F. As shown in FIGS. 1 and 3, the boundary 22x between the second region 22b and the first region 22a is located between the third electrode 53 and the second electrode 52. The position of the boundary 22x in the second direction D2 is between the position of the third electrode 53 in the second direction D2 and the position of the second electrode portion 52b in the second direction D2. For example, at least part of the first region 22a does not overlap the second electrode portion 52b in the third direction D3. A high electric field tends to concentrate at the end of the second electrode portion 52b on the third electrode 53 side. By the position of the boundary 22x being on the side of the third electrode 53, it is possible to more stably suppress traps that cause changes in characteristics. It is easier to obtain stable characteristics.

As shown in FIG. 3, in this example, no region including fluorine is provided under the first electrode portion 52a. For example, the second semiconductor portion 22 may further include a third region 22c. The third region 22c is located between the second partial region 12 and the first electrode portion 52a in the third direction D3. The concentration of fluorine in the third region 22c is lower than the concentration of fluorine in the first region 22a. Alternatively, the third region 22c does not include fluorine. For example, low contact resistance can be obtained because the region overlapping the first electrode portion 52a does not include fluorine. This makes it easier to obtain low on-resistance.

As shown in FIG. 3, the second semiconductor portion 22 may further include a fourth region 22d. The fourth region 22d is located between the first semiconductor region 10 and the first region 22a in the third direction D3. The concentration of fluorine in the fourth region 22d is lower than the concentration of fluorine in the first region 22a. Alternatively, the fourth region 22d does not include fluorine.

For example, a region with a high fluorine concentration (first region 22a) may be locally provided on the surface side of the second semiconductor portion 22. Traps that affect the characteristics tend to occur on the surface side of the second semiconductor portion 22. By locally providing a region with a high fluorine concentration (first region 22a) on the surface side of the second semiconductor portion 22, changes in characteristics can be effectively suppressed. By providing the fourth region 22d with a low fluorine concentration, for example, low on-resistance can be easily obtained.

As shown in FIG. 3, the semiconductor device 110 may further include a first insulating member 41. At least a part of the first insulating member 41 is located between the first region 22a and the second electrode portion 52b.

A portion 41p of the first insulating member 41 is located between the first region 22a and the second electrode portion 52b. Another portion 41q of the first insulating member 41 does not overlap the second electrode 52 in the third direction D3. The thickness along the third direction D3 of the portion 41p of the first insulating member 41 is defined as a thickness t41p. The thickness along the third direction D3 of the other portion 41q of the first insulating member 41 is defined as a thickness t41q. The thickness t41p is thinner than the thickness t41q. The portion 41p of the first insulating member 41 overlaps the first region 22a. Even when such a difference in thickness is provided, stable characteristics can be effectively obtained by providing the first region 22a.

In this example, the first insulating member 41 includes a first insulating portion 41a and a second insulating portion 41b. At least part of the first insulating portion 41a is located between the second semiconductor portion 22 and the second insulating portion 41b in the third direction D3. The first insulating portion 41a does not overlap the second electrode portion 52b in the third direction D3. A part of the second insulating portion 41b is located between the first region 22a and the second electrode portion 52b in the third direction D3. This part of the second insulating portion 41b is located between the first insulating portion 41a and the first electrode portion 52a in the second direction D2. In this way, a stacked structure may be applied to the first insulating member 41.

In one example, the first insulating portion 41a can be formed by CVD (for example, LPCVD: Low-Pressure Chemical Vapor Deposition). The second insulating portion 41b can be formed, for example, by CVD (for example, PECVD: plasma-enhanced chemical vapor deposition). For example, the film quality of the first insulating portion 41a is higher than the film quality of the second insulating portion 41b. It is easier to obtain more stable characteristics. The first insulating member 41 (the first insulating portion 41a and the second insulating portion 41b) may include silicon and nitrogen, for example. The first insulating portion 41a and the second insulating portion 41b include, for example, silicon nitride. It is easy to obtain stable characteristics. The first insulating member 41 (the first insulating portion 41a and the second insulating portion 41b) may include silicon and oxygen, for example.

As shown in FIG. 2, a part of the first insulating portion 41a may be provided between the second semiconductor region 20 and the third electrode 53 in the third direction D3. This part of the first insulating portion 41a overlaps the third electrode 53 in the third direction D3. This part of the first insulating portion 41a functions as, for example, a gate insulating film.

As shown in FIG. 2, in this example, the third electrode 53 includes a third electrode portion 53c and a fourth electrode portion 53d. In this example, the third electrode portion 53c is in contact with a part of the first insulating portion 41a. The fourth electrode portion 53d is electrically connected to the third electrode portion 53c. The fourth electrode portion 53d is, for example, an eaves portion.

As shown in FIG. 2, in this example, the first electrode 51 includes a fifth electrode portion 51e and a sixth electrode portion 51f. The fifth electrode portion 51e is electrically connected to the first partial region 11 (and the first semiconductor portion 21). The sixth electrode portion 51f is electrically connected to the fifth electrode portion 51e. The sixth electrode portion 51f is, for example, an eaves portion.

As shown in FIG. 2, the semiconductor device 110 may include a base 18s and a nitride layer 18b. The first semiconductor region 10 is provided between the base 18s and the second semiconductor region 20. The nitride layer 18b is provided between the base 18s and the first semiconductor region 10. The base 18s may be, for example, a silicon substrate. The nitride layer 18b includes, for example, Al, Ga, and nitrogen. The nitride layer 18b includes AlGaN, for example. This AlGaN layer is, for example, a buffer layer. The nitride layer 18b includes a region facing the first semiconductor region 10. This region may include a GaN layer including carbon.

For example, in a first sample including the configuration illustrated in FIG. 3, the on-resistance after the voltage stress test is three times the initial value before the voltage stress test. In a second sample in which the first region 22a is not provided, the on-resistance after the voltage stress test is six times the initial value before the voltage stress test. By providing the first region 22a, the change in on-resistance is reduced to ½. In the voltage stress test, a drain voltage of the rated voltage is applied for 1000 seconds in a state of the gate off.

Hereinafter, some examples of various configurations of the region including the second electrode will be described.

FIG. 4 is a schematic cross-sectional view illustrating a part of a semiconductor device according to the first embodiment.

As shown in FIG. 4, in a semiconductor device 111 according to the embodiment, the first insulating member 41 includes the first insulating portion 41a and the second insulating portion 41b. A part of the second insulating portion 41b is located between the first region 22a and the second electrode portion 52b in the third direction D3. The fluorine concentration in this part of the second insulating portion 41b is higher than the fluorine concentration in the first insulating portion 41a. Alternatively, this portion of the second insulating portion 41b includes fluorine and the first insulating portion 41a does not include fluorine. Thus, the second insulating portion 41b overlapping the first region 22a may include fluorine. The first region 22a including fluorine can be stably obtained easily. In one example, fluorine may be supplied to the first region 22a from the second insulating portion 41b including fluorine.

FIG. 5 is a schematic cross-sectional view illustrating a part of a semiconductor device according to the first embodiment.

As shown in FIG. 5, in a semiconductor device 112 according to the embodiment, the second partial region 12 is in contact with the first electrode portion 52a. A direction from the second semiconductor portion 22 to at least a part of the first electrode portion 52a is along the second direction D2. Also in such a semiconductor device 112, the first region 22a including fluorine is provided.

FIG. 6 is a schematic cross-sectional view illustrating a part of a semiconductor device according to the first embodiment.

As shown in FIG. 6, in a semiconductor device 113 according to the embodiment, a part of the first region 22a is provided between the second partial region 12 and the first electrode portion 52a in the third direction D3. In this way, the first region 22a including fluorine may be provided also under the first electrode portion 52a.

FIG. 7 is a schematic cross-sectional view illustrating a part of a semiconductor device according to the first embodiment.

As shown in FIG. 7, in a semiconductor device 114 according to the embodiment, the first region 22a may be provided between the first semiconductor region 10 and the first insulating portion 41a.

Other configurations described with respect to the semiconductor device 110 may be applied to the semiconductor devices 111 to 114 described above.

FIG. 8 is a schematic cross-sectional view illustrating a part of a semiconductor device according to the first embodiment.

As shown in FIG. 8, in a semiconductor device 115 according to the embodiment, the second electrode 52 includes a nitride region 52N and a conductive region 52C. A part of the nitride region 52N is provided between the second partial region 12 and the conductive region 52C. Another part of the nitride region 52N is provided between a part of the second insulating portion 41b and the second electrode portion 52b. The material of nitride region 52N is different from the material of conductive region 52C.

For example, the nitride region 52N includes gallium and nitrogen. The nitride region 52N is n-type GaN. The conductive region 52C is, for example, metal. In this way, a part of the second electrode 52 may include a semiconductor. For example, it becomes easier to obtain lower on-resistance.

Also in the semiconductor device 115, the first region 22a including fluorine is provided. Stable characteristics can be obtained. In the semiconductor device 115, the configuration described with respect to the semiconductor devices 110 to 114 may be applied.

FIG. 9 is a schematic cross-sectional view illustrating a semiconductor device according to the first embodiment.

As shown in FIG. 9, a semiconductor device 120 according to the embodiment includes a second electrode conductive member 52P, the first insulating member 41, and a second insulating member 42. The configurations of the semiconductor devices 110 to 115 may be applied to the configurations excluding the second electrode conductive member 52P and the second insulating member 42.

In semiconductor device 120, second electrode conductive member 52P is electrically connected to second electrode 52. At least a part of the first insulating member 41 is provided between the second semiconductor portion 22 and the second electrode portion 52b. At least a part of the second insulating member 42 is provided between the second electrode portion 52b and the second electrode conductive member 52P. The second electrode conductive member 52P functions, for example, as a field plate. The concentration of electric field is further relaxed.

The first insulating member 41 includes silicon and nitrogen. The second insulating member 42 includes silicon and oxygen. The concentration of nitrogen in the second insulating member 42 is lower than the concentration of nitrogen in the first insulating member 41. Alternatively, the second insulating member 42 does not include nitrogen. With such a plurality of insulating members, more stable characteristics can be easily obtained.

As shown in FIG. 9, a first electrode conductive member 51P may be provided. The first electrode conductive member 51P is electrically connected to the first electrode 51. In this example, the first electrode conductive member 51P is electrically connected to the first electrode 51 at a position different from the cross section shown in FIG. 9. Another first electrode conductive member 51Q may be provided. The other first electrode conductive member 51Q is electrically connected to the first electrode 51.

For example, the second semiconductor portion 22 may include a region that overlaps the first electrode conductive member 51P. This region may include fluorine. Trap generation is further suppressed. This makes it easier to obtain stable characteristics.

As shown in FIG. 9, a third insulating member 43 may be provided on the second electrode conductive member 52P, the first electrode conductive member 51P, and the second insulating member. The third insulating member 43 may include, for example, silicon nitride.

FIG. 10 is a schematic cross-sectional view illustrating a semiconductor device according to the first embodiment.

As shown in FIG. 10, in a semiconductor device 121 according to the embodiment, at least a part of the third electrode 53 is provided between the first semiconductor portion 21 and the second semiconductor portion 22 in the second direction D2. For example, at least a part of the third electrode 53 is provided between the fourth partial region 14 and the fifth partial region 15 in the second direction D2. In the semiconductor device 121, the third electrode 53 is, for example, For example, a high threshold a recessed gate electrode. voltage can be obtained. Also in the semiconductor device 121, the first region 22a including fluorine is provided. Stable characteristics can be obtained.

In the semiconductor device 121, a part of the first insulating portion 41a is provided between the first semiconductor portion 21 and at least a part of the third electrode 53 in the second direction D2. Another part of the first insulating portion 41a is provided between at least a part of the third electrode 53 and the second semiconductor portion 22 in the second direction D2.

Second Embodiment

The second embodiment relates to a method for manufacturing a semiconductor device. Below, a method of manufacturing a portion including the second electrode 52 will be described.

FIGS. 11A and 11B are schematic cross-sectional views illustrating a method for manufacturing a semiconductor device according to the second embodiment.

As shown in FIG. 11A, in a method for manufacturing a semiconductor device according to the embodiment, a structure body 10B is prepared.

The structure body 10B includes the first semiconductor region 10 including Al_x1Ga_1−x1N (0≤x1<1), the second semiconductor region 20 including Al_x2Ga_1−x2N (0<x2<1, x1<x2), and a first insulating film 41f. The second semiconductor region 20 includes the first region 22a and the second region 22b. The second region 22b is located between the first semiconductor region 10 and the first insulating film 41f. The first region 22a is not covered with the first insulating film 41f.

As shown in FIG. 11A, fluorine is introduced into the first region 22a. For example, fluorine may be introduced by ion implantation using the first insulating film 41f as a mask. The concentration of fluorine in the first region 22a is higher than the concentration of fluorine in the second region 22b. Alternatively, the first region 22a includes fluorine and the second region 22b does not include fluorine.

As shown in FIG. 11B, an electrode 50 is formed. The electrode 50 includes the first electrode portion 52a and the second electrode portion 52b. The first electrode portion 52a is electrically connected to a part of the first semiconductor region 10. The second electrode portion 52b is electrically connected to the first electrode portion 52a. The second electrode portion 52b overlaps the first region 22a in a direction from the first semiconductor region 10 to the second semiconductor region 20 (the third direction D3).

Thus, for example, the semiconductor device 110 is obtained. According to the embodiments, it is possible to provide a method of manufacturing a semiconductor device capable of improving characteristics.

In the above, the electrode 50 corresponds to the second electrode 52. The first insulating film 41f corresponds to, for example, the first insulating portion 41a. The second insulating portion 41b may be formed before forming the electrode 50.

FIGS. 12A and 12B are schematic cross-sectional views illustrating a method for manufacturing a semiconductor device according to the second embodiment.

As shown in FIG. 12A, the structure body 10B is prepared in a method for manufacturing a semiconductor device according to the embodiment. In this example, the structure body 10B further includes a second insulating film 42f. The first insulating film 41f is provided between the second region 22b and a part of the second insulating film 42f. The first insulating film 41f is not provided between the first region 22a and the second insulating film 42f. The second insulating film 42f includes fluorine.

As shown in FIG. 12B, fluorine is moved from the second insulating film 42f to the first region 22a. For example, fluorine moves from the second insulating film 42f to the first region 22a by diffusion due to heat treatment or the like. Thereby, the first region 22a including fluorine is obtained. At this time, the movement of fluorine is suppressed by the first insulating film 41f. As a result, the concentration of fluorine in the second region 22b is low. Alternatively, the second region 22b does not substantially include fluorine.

Thus, introducing fluorine may include moving at least a part of the fluorine included in the second insulating film 42f to the first region 22a. For example, the semiconductor device 110 can be obtained by such a manufacturing method.

Information regarding length and thickness can be obtained by electron microscopy or the like. Information on the composition of materials can be obtained by SIMS (Secondary Ion Mass Spectrometry) or EDX (Energy dispersive X-ray spectroscopy).

Embodiments may include the following configurations (e.g., technical proposals).

(Configuration 1)

A semiconductor device, comprising:

a first electrode extending in a first direction;

a second electrode extending in the first direction, a second direction from the first electrode to the second electrode being perpendicular to the first direction;

a third electrode extending in the first direction, a position of the third electrode in the second direction being between a position of the first electrode in the second direction and a position of the second electrode in the second direction;

a first semiconductor region including Al_x1Ga_1−x1N (0≤x1<1), the first semiconductor region including a first partial region, a second partial region, a third partial region, a fourth partial region, and a fifth partial region, a third direction from the first partial region to the first electrode crossing a plane including the first direction and the second direction, a direction from the second partial region to the second electrode being along the third direction, a direction from the third partial region to the third electrode being along the third direction, a position of the fourth partial region in the second direction being between a position of the first partial region in the second direction and a position of the third partial region in the second direction, a position of the fifth partial region in the second direction bring between the position of the third partial region in the second direction and a position of the second partial region in the second direction; and a second semiconductor region including Al_x2Ga_1−x2N (0<x2<1, x1<x2), the second semiconductor region including a first semiconductor portion and a second semiconductor portion, a direction from the fourth partial region to the first semiconductor portion being along the third direction, a direction from the fifth partial region to the second semiconductor portion being along the third direction, the second semiconductor portion including a first region and a second region, a position of the first region in the second direction being between a position of the second region in the second direction and the position of the second electrode in the second direction, a concentration of fluorine in the first region being higher than a concentration of fluorine in the second region, or the first region including fluorine and the second region not including fluorine.

(Configuration 2)

The semiconductor device according to Configuration 1, wherein

the second electrode includes a first electrode portion and a second electrode portion,

a direction from the first region to at least a part of the first electrode portion is along the second direction, and

at least a part of the first region is provided between the first semiconductor region and the second electrode portion in the third direction.

(Configuration 3)

The semiconductor device according to Configuration 2, wherein

a position of a boundary between the second region and the first region in the second direction is located between the position of the third electrode in the second direction and a position of the second electrode portion in the second direction.

(Configuration 4)

The semiconductor device according to Configuration 3, wherein

at least a part of the first region does not overlap the second electrode portion in the third direction.

(Configuration 5)

The semiconductor device according to any one of Configurations 2-4, wherein

a part of the first region is provided between the second partial region and the first electrode portion in the third direction.

(Configuration 6)

The semiconductor device according to any one of Configurations 2-4, wherein

the second semiconductor portion further includes a third region,

the third region is provided between the second partial region and the first electrode portion in the third direction, and

a concentration of fluorine in the third region is lower than the concentration of fluorine in the first region, or the third region does not include fluorine.

(Configuration 7)

The semiconductor device according to any one of Configurations 2-5, wherein

the second partial region is in contact with the first electrode portion, and

a direction from the second semiconductor portion to at least a part of the first electrode portion is along the second direction.

(Configuration 8)

The semiconductor device according to any one of Configurations 1-7, wherein

the second semiconductor portion further includes a fourth region,

the fourth region is provided between the first semiconductor region and the first region in the third direction, and

a concentration of fluorine in the fourth region is lower than the concentration of fluorine in the first region, or the fourth region does not include fluorine.

(Configuration 9)

The semiconductor device according to any one of Configurations 2-5, further comprising:

a first insulating member,

at least a part of the first insulating member being provided between the first region and the second electrode portion.

(Configuration 10)

The semiconductor device according to Configuration 9, wherein

a part of the first insulating member is provided between the first region and the second electrode portion,

another part of the first insulating member does not overlap the second electrode in the third direction, and

a thickness of the part of the first insulating member along the third direction is thinner than the thickness of the other part of the first insulating member along the third direction.

(Configuration 11)

The semiconductor device according to any one of Configurations 2-5, further comprising:

a second electrode conductive member electrically connected to the second electrode;

a first insulating member; and

a second insulating member,

at least a part of the first insulating member being provided between the second semiconductor portion and the second electrode portion,

at least a part of the second insulating member being provided between the second electrode portion and the second electrode conductive member,

the first insulating member including silicon and nitrogen,

the second insulating member including silicon and oxygen, and

a concentration of nitrogen in the second insulating member being lower than a concentration of nitrogen in the first insulating member, or the second insulating member not including nitrogen.

(Configuration 12)

The semiconductor device according to any one of Configurations 2-5, further comprising:

a first insulating member,

the first insulating member including a first insulating portion and a second insulating portion,

at least a part of the first insulating portion being provided between the second semiconductor portion and the second insulating portion in the third direction,

the first insulating portion not overlapping the second electrode portion in the third direction,

a part of the second insulating portion being provided between the first region and the second electrode portion in the third direction, and

the part of the second insulating part being provided between the first insulating portion and the first electrode portion in the second direction.

(Configuration 13)

The semiconductor device according to Configuration 12, wherein

a concentration of fluorine in the part of the second insulating portion is higher than a concentration of fluorine in the first insulating portion, or

the part of the second insulating portion includes fluorine, and the first insulating portion does not include fluorine.

(Configuration 14)

The semiconductor device according to Configuration 12 or 13, wherein

a part of the first insulating portion is provided between the second semiconductor region and the third electrode in the third direction.

(Configuration 15)

The semiconductor device according to any one of Configurations 12-14, wherein

the second electrode includes a nitride region and a conductive region,

a part of the nitride region is provided between the second partial region and the conductive region,

another part of the nitride region is provided between the part of the second insulating part and the second electrode part, and

the nitride region includes gallium and nitrogen.

(Configuration 16)

The semiconductor device according to any one of Configurations 1-10, wherein

the second electrode includes a nitride region and a conductive region,

the nitride region is provided between the second partial region and the conductive region, and

the nitride region includes gallium and nitrogen.

(Configuration 17)

The semiconductor device according to any one of Configurations 1-15, wherein

a concentration of fluorine in the first region is not less than 1×10¹⁶ cm⁻³ and not more than 1×10¹⁸ cm⁻³.

(Configuration 18)

The semiconductor device according to any one of Configurations 1-13, wherein

at least a part of the third electrode is provided between the first semiconductor portion and the second semiconductor portion in the second direction.

(Configuration 19)

A method for manufacturing a semiconductor device, the method comprising:

preparing a structure body, the structure body including a first semiconductor region including Al_x1Ga_1−x1N (0≤x1<1), a second semiconductor region including Al_x2Ga_1−x2N (0<x2<1, x1<x2), and a first insulating film, the second semiconductor region includes a first region and a second region, the second region being between the first semiconductor region and the first insulating film, the first region being not covered with the first insulating film;

introducing fluorine into the first region, a concentration of fluorine in the first region being higher than a concentration of fluorine in the second region, or the first region including fluorine and the second region not including fluorine; and

forming an electrode, the electrode including a first electrode portion and a second electrode portion, the first electrode portion being electrically connected to a part of the first semiconductor region, the second electrode portion being electrically connected to the first electrode portion, the second electrode portion overlapping the first region in a direction from the first semiconductor region to the second semiconductor region.

(Configuration 20)

The method according to Configuration 19, wherein

the structure body further includes a second insulating film,

the first insulating film is provided between the second region and a part of the second insulating film,

the first insulating film is not provided between the first region and the second insulating film,

the second insulating film includes fluorine, and

the introducing the fluorine includes causing at least a part of the fluorine included in the second insulating film to move to the first region.

According to the embodiments, a semiconductor device whose characteristics can be improved and a method for manufacturing the same are provided.

Hereinabove, exemplary embodiments of the invention are described with reference to specific examples. However, the embodiments of the invention are not limited to these specific examples. For example, one skilled in the art may similarly practice the invention by appropriately selecting specific configurations of components included in the semiconductor devices such as electrodes, semiconductor regions, insulating members, etc., from known art. Such practice is included in the scope of the invention to the extent that similar effects thereto are obtained.

Further, any two or more components of the specific examples may be combined within the extent of technical feasibility and are included in the scope of the invention to the extent that the purport of the invention is included.

Moreover, all semiconductor devices and methods for manufacturing the same practicable by an appropriate design modification by one skilled in the art based on the semiconductor devices and the methods for manufacturing the same described above as embodiments of the invention also are within the scope of the invention to the extent that the purport of the invention is included.

Various other variations and modifications can be conceived by those skilled in the art within the spirit of the invention, and it is understood that such variations and modifications are also encompassed within the scope of the invention.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention.

Claims

1. A semiconductor device, comprising: a first electrode extending in a first direction;a second electrode extending in the first direction, a second direction from the first electrode to the second electrode being perpendicular to the first direction;a third electrode extending in the first direction, a position of the third electrode in the second direction being between a position of the first electrode in the second direction and a position of the second electrode in the second direction;a first semiconductor region including Alx1Ga1−x1N (0≤x1<1), the first semiconductor region including a first partial region, a second partial region, a third partial region, a fourth partial region, and a fifth partial region, a third direction from the first partial region to the first electrode crossing a plane including the first direction and the second direction, a direction from the second partial region to the second electrode being along the third direction, a direction from the third partial region to the third electrode being along the third direction, a position of the fourth partial region in the second direction being between a position of the first partial region in the second direction and a position of the third partial region in the second direction, a position of the fifth partial region in the second direction bring between the position of the third partial region in the second direction and a position of the second partial region in the second direction; anda second semiconductor region including Alx2Ga1−x2N (0<x2<1, x1<x2), the second semiconductor region including a first semiconductor portion and a second semiconductor portion, a direction from the fourth partial region to the first semiconductor portion being along the third direction, a direction from the fifth partial region to the second semiconductor portion being along the third direction, the second semiconductor portion including a first region and a second region, a position of the first region in the second direction being between a position of the second region in the second direction and the position of the second electrode in the second direction, a concentration of fluorine in the first region being higher than a concentration of fluorine in the second region, or the first region including fluorine and the second region not including fluorine.

2. The device according to claim 1, wherein the second electrode includes a first electrode portion and a second electrode portion,a direction from the first region to at least a part of the first electrode portion is along the second direction, andat least a part of the first region is provided between the first semiconductor region and the second electrode portion in the third direction.

3. The device according to claim 2, wherein a position of a boundary between the second region and the first region in the second direction is located between the position of the third electrode in the second direction and a position of the second electrode portion in the second direction.

4. The device according to claim 3, wherein at least a part of the first region does not overlap the second electrode portion in the third direction.

5. The device according to claim 2, wherein a part of the first region is provided between the second partial region and the first electrode portion in the third direction.

6. The device according to claim 2, wherein the second semiconductor portion further includes a third region,the third region is provided between the second partial region and the first electrode portion in the third direction, anda concentration of fluorine in the third region is lower than the concentration of fluorine in the first region, or the third region does not include fluorine.

7. The device according to claim 2, wherein the second partial region is in contact with the first electrode portion, anda direction from the second semiconductor portion to at least a part of the first electrode portion is along the second direction.

8. The device according to claim 1, wherein the second semiconductor portion further includes a fourth region,the fourth region is provided between the first semiconductor region and the first region in the third direction, anda concentration of fluorine in the fourth region is lower than the concentration of fluorine in the first region, or the fourth region does not include fluorine.

9. The device according to claim 2, further comprising: a first insulating member,at least a part of the first insulating member being provided between the first region and the second electrode portion.

10. The device according to claim 9, wherein a part of the first insulating member is provided between the first region and the second electrode portion,another part of the first insulating member does not overlap the second electrode in the third direction, anda thickness of the part of the first insulating member along the third direction is thinner than the thickness of the other part of the first insulating member along the third direction.

11. The device according to claim 2, further comprising: a second electrode conductive member electrically connected to the second electrode;a first insulating member; anda second insulating member,at least a part of the first insulating member being provided between the second semiconductor portion and the second electrode portion,at least a part of the second insulating member being provided between the second electrode portion and the second electrode conductive member,the first insulating member including silicon and nitrogen,the second insulating member including silicon and oxygen, anda concentration of nitrogen in the second insulating member being lower than a concentration of nitrogen in the first insulating member, or the second insulating member not including nitrogen.

12. The device according to claim 2, further comprising: a first insulating member,the first insulating member including a first insulating portion and a second insulating portion,at least a part of the first insulating portion being provided between the second semiconductor portion and the second insulating portion in the third direction,the first insulating portion not overlapping the second electrode portion in the third direction,a part of the second insulating portion being provided between the first region and the second electrode portion in the third direction, andthe part of the second insulating part being provided between the first insulating portion and the first electrode portion in the second direction.

13. The device according to claim 12, wherein a concentration of fluorine in the part of the second insulating portion is higher than a concentration of fluorine in the first insulating portion, orthe part of the second insulating portion includes fluorine, and the first insulating portion does not include fluorine.

14. The device according to claim 12, wherein a part of the first insulating portion is provided between the second semiconductor region and the third electrode in the third direction.

15. The device according to claim 12, wherein the second electrode includes a nitride region and a conductive region,a part of the nitride region is provided between the second partial region and the conductive region,another part of the nitride region is provided between the part of the second insulating part and the second electrode part, andthe nitride region includes gallium and nitrogen.

16. The device according to claim 1, wherein the second electrode includes a nitride region and a conductive region,the nitride region is provided between the second partial region and the conductive region, andthe nitride region includes gallium and nitrogen.

17. The device according to claim 1, wherein a concentration of fluorine in the first region is not less than 1×1016 cm−3 and not more than 1×1018 cm−3.

18. The device according to claim 1, wherein at least a part of the third electrode is provided between the first semiconductor portion and the second semiconductor portion in the second direction.

19. A method for manufacturing a semiconductor device, the method comprising: preparing a structure body, the structure body including a first semiconductor region including Alx1Ga1−x1N (0≤x1<1), a second semiconductor region including Alx2Ga1−x2N (0<x2<1, x1<x2), and a first insulating film, the second semiconductor region includes a first region and a second region, the second region being between the first semiconductor region and the first insulating film, the first region being not covered with the first insulating film;introducing fluorine into the first region, a concentration of fluorine in the first region being higher than a concentration of fluorine in the second region, or the first region including fluorine and the second region not including fluorine; andforming an electrode, the electrode including a first electrode portion and a second electrode portion, the first electrode portion being electrically connected to a part of the first semiconductor region, the second electrode portion being electrically connected to the first electrode portion, the second electrode portion overlapping the first region in a direction from the first semiconductor region to the second semiconductor region.

20. The method according to claim 19, wherein the structure body further includes a second insulating film,the first insulating film is provided between the second region and a part of the second insulating film,the first insulating film is not provided between the first region and the second insulating film,the second insulating film includes fluorine, andthe introducing the fluorine includes causing at least a part of the fluorine included in the second insulating film to move to the first region.