The present invention relates to a semiconductor device and a manufacturing method thereof, and more particularly, to a semiconductor device including a III-V compound semiconductor layer and a manufacturing method thereof.
Because of the semiconductor characteristics, III-V semiconductor compounds may be applied in many kinds of integrated circuit devices, such as high power field effect transistors, high frequency transistors, or high electron mobility transistors (HEMTs). In the high electron mobility transistor, two semiconductor materials with different band-gaps are combined and heterojunction is formed at the junction between the semiconductor materials as a channel for carriers. In recent years, gallium nitride (GaN) based materials have been applied in the high power and high frequency products because of the properties of wider band-gap and high saturation velocity. Two-dimensional electron gas (2DEG) may be generated by the piezoelectricity property of the GaN-based materials, and the switching velocity may be enhanced because of the higher electron velocity and the higher electron density of the 2DEG. Therefore, how to further improve the electrical performance of transistors formed with III-V compound materials by modifying materials, structures and/or manufacturing methods has become a research direction for people in the related fields.
A semiconductor device and a manufacturing method thereof are provided in the present invention. A p-type doped III-V compound material is formed in an opening penetrating through a protection layer for reducing negative influence of related manufacturing processes of forming the p-type doped III-V and/or other subsequent manufacturing processes on other material layers. For example, the amount of dopants diffused from the p-type doped III-V compound material into the III-V compound barrier layer and/or the III-V compound semiconductor layer may be reduced by covering most of the III-V compound barrier layer with the protection layer. Additionally, the damage to the III-V compound barrier layer and/or the III-V compound semiconductor layer in other related manufacturing processes (such as an etching process, but not limited thereto) may be reduced accordingly. Therefore, the purposes of increasing the concentration of two-dimensional electron gas (2DEG), enhancing the drain current (Ids) of the semiconductor device, and/or lowering the leakage current of the semiconductor device may be achieved.
According to an embodiment of the present invention, a manufacturing method of a semiconductor device is provided. The manufacturing method includes the following steps. A III-V compound barrier layer is formed on a III-V compound semiconductor layer. A protection layer is formed on the III-V compound barrier layer. An opening is formed penetrating through the protection layer in a vertical direction and exposes a part of the III-V compound barrier layer. A p-type doped III-V compound material is formed in the opening. A patterned barrier layer is formed on the p-type doped III-V compound material. A contact area between the patterned barrier layer and the p-type doped III-V compound material is less than an area of a top surface of the p-type doped III-V compound material.
According to an embodiment of the present invention, a semiconductor device is provided. The semiconductor device includes a III-V compound semiconductor layer, a III-V compound barrier layer, a protection layer, an opening, a p-type doped III-V compound material, and a patterned barrier layer. The III-V compound barrier layer is disposed on the III-V compound semiconductor layer. The protection layer is disposed on the III-V compound barrier layer. The opening penetrates through the protection layer in a vertical direction. The p-type doped III-V compound material is disposed in the opening. The patterned barrier layer is disposed on the p-type doped III-V compound material. A contact area between the patterned barrier layer and the p-type doped III-V compound material is less than an area of a top surface of the p-type doped III-V compound material.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
The present invention has been particularly shown and described with respect to certain embodiments and specific features thereof. The embodiments set forth herein below are to be taken as illustrative rather than limiting. It should be readily apparent to those of ordinary skill in the art that various changes and modifications in form and detail may be made without departing from the spirit and scope of the present invention.
Before the further description of the preferred embodiment, the specific terms used throughout the text will be described below.
The terms “on,” “above,” and “over” used herein should be interpreted in the broadest manner such that “on” not only means “directly on” something but also includes the meaning of “on” something with an intermediate feature or a layer therebetween, and that “above” or “over” not only means the meaning of “above” or “over” something but can also include the meaning it is “above” or “over” something with no intermediate feature or layer therebetween (i.e., directly on something).
The ordinal numbers, such as “first”, “second”, etc., used in the description and the claims are used to modify the elements in the claims and do not themselves imply and represent that the claim has any previous ordinal number, do not represent the sequence of some claimed element and another claimed element, and do not represent the sequence of the manufacturing methods, unless an addition description is accompanied. The use of these ordinal numbers is only used to make a claimed element with a certain name clear from another claimed element with the same name.
The term “etch” is used herein to describe the process of patterning a material layer so that at least a portion of the material layer after etching is retained. When “etching” a material layer, at least a portion of the material layer is retained after the end of the treatment. In contrast, when the material layer is “removed”, substantially all the material layer is removed in the process. However, in some embodiments, “removal” is considered to be a broad term and may include etching.
The term “forming” or the term “disposing” are used hereinafter to describe the behavior of applying a layer of material to the substrate. Such terms are intended to describe any possible layer forming techniques including, but not limited to, thermal growth, sputtering, evaporation, chemical vapor deposition, epitaxial growth, electroplating, and the like.
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Specifically, the manufacturing method in this embodiment may include but is not limited to the following steps. In some embodiments, the III-V compound semiconductor layer 14 described above may be formed on a substrate 10. The substrate 10 may have a top surface 10T and a bottom surface 10B opposite to the top surface 10T in the direction D1, and III-V compound semiconductor layer 14, the III-V compound barrier layer 16, and the protection layer 24 may be formed at a side of the top surface 10T. In addition, the substrate 10 may include a silicon substrate, a silicon carbide (SiC) substrate, a gallium nitride (GaN) substrate, a sapphire substrate, or a substrate made of other suitable materials. In some embodiments, a buffer layer 12 may be formed on the substrate 10 before the step of forming the III-V compound semiconductor layer 14, and the buffer layer 12 may be located between the substrate 10 and the III-V compound semiconductor layer 14 in the direction D1. The buffer layer 12 may include gallium nitride, aluminum gallium nitride (AlGaN), aluminum indium nitride (AlInN), or other suitable buffer materials.
In some embodiments, the direction D1 described above may be regarded as a thickness direction of the substrate 10, and a horizontal direction substantially orthogonal to the direction D1 (such as a direction D2 and other directions orthogonal to the direction D1) may be substantially parallel with the top surface 10T and/or the bottom surface 10B of the substrate 10, but not limited thereto. In this description, a distance between the bottom surface 10B of the substrate 10 and a relatively higher location and/or a relatively higher part in the vertical direction (such as the direction D1) may be greater than a distance between the bottom surface 10B of the substrate 10 and a relatively lower location and/or a relatively lower part in the direction D1. The bottom or a lower portion of each component may be closer to the bottom surface 10B of the substrate 10 in the direction D1 than the top or upper portion of this component. Another component disposed above a specific component may be regarded as being relatively far from the bottom surface 10B of the substrate 10 in the direction D1, and another component disposed under a specific component may be regarded as being relatively close to the bottom surface 10B of the substrate 10 in the direction D1.
In some embodiments, the III-V compound semiconductor layer 14 may include gallium nitride, indium gallium nitride (InGaN), or other suitable III-V compound semiconductor materials. The III-V compound barrier layer 16 may include aluminum gallium nitride, aluminum indium nitride, aluminum gallium indium nitride (AlGaInN), aluminum nitride (AlN), or other suitable III-V compound materials. The protection layer 24 may include oxide dielectric material (such as silicon oxide), nitride dielectric material (such as silicon nitride), or other suitable dielectric materials or insulation materials. As shown in
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Subsequently, a planarization process 91 may be performed to the p-type doped III-V compound layer 26 for removing the p-type doped III-V compound layer 26 formed outside the opening OP, and the p-type doped III-V compound layer 26 remains in the opening OP after the planarization process 91 may become the p-type doped III-V compound material 26P described above. The planarization process 91 may include a chemical mechanical polishing (CMP) process, an etching back process, or other suitable planarization approaches. Additionally, after the planarization process 91, a top surface 26T of the p-type doped III-V compound material 26P and a top surface 24T of the protection layer 24 may be substantially coplanar, but not limited thereto. It is worth noting that most of the III-V compound barrier layer 16 may be covered by the protection layer 24 without directly contacting the p-type doped III-V compound layer 26 during the formation of the p-type doped III-V compound layer 26, and the negative influence on the III-V compound barrier layer 16 and/or the III-V compound semiconductor layer 14, which is induced from the p-type doped III-V compound layer 26 and/or the related processes for forming the p-type doped III-V compound layer 26, may be reduced accordingly. For example, the amount of the p-type dopants diffused from the p-type doped III-V compound layer 26 into the III-V compound barrier layer 16 and/or the III-V compound semiconductor layer 14 may be reduced by covering most of the III-V compound barrier layer 16 with the protection layer 24, and the electrical performance of the semiconductor device may be improved accordingly. For instance, the concentration of two-dimensional electron gas (2DEG) in the III-V compound semiconductor layer 14 may be increased for enhancing the drain current (Ids) of the semiconductor device, but not limited thereto. In addition, the damage to other material layers (such as the III-V compound barrier layer 16 and/or the III-V compound semiconductor layer 14) in the related processes for forming the p-type doped III-V compound material 26P and/or other subsequent processes may be reduced by forming the protection layer 24, and the manufacturing yield and/or the operation performance of the semiconductor device may be improved accordingly.
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However, in some embodiments, the contact area between the patterned barrier layer 32P and the p-type doped III-V compound material 26P may be greater than or equal to the area of the top surface 26T of the p-type doped III-V compound material 26P when the etching process 92 described above is performed without performing the etching process 93. In other words, a projection area of the patterned barrier layer 32P in the direction D1 may be greater than or equal to a projection area of the p-type doped III-V compound material 26P in the direction D1, and the top surface 26T of the p-type doped III-V compound material 26P may be covered by the patterned barrier layer 32P without being exposed. Relatively, after the etching process 93 described above, the projection area of the patterned barrier layer 32P′ in the direction D1 may be smaller than the projection area of the p-type doped III-V compound material 26P in the direction D1, and a part of the top surface 26T of the p-type doped III-V compound material 26P may not be covered by the patterned barrier layer 32P′ and may be exposed accordingly. Additionally, it is worth noting that, during the step of forming the patterned barrier layer 32P or the patterned barrier layer 32P′, the III-V compound barrier layer 16 may be covered by the protection layer 24 and the p-type doped III-V compound material 26P for reducing the etching damage to the III-V compound barrier layer 16 and/or the III-V compound semiconductor layer 14 in the etching process 92 and/or the etching process 93. The electrical performance of the semiconductor device may be improved accordingly. For example, the purposes of increasing the concentration of two-dimensional electron gas (2DEG), enhancing the drain current (Ids) of the semiconductor device, and/or lowering the leakage current of the semiconductor device may be achieved, but not limited thereto.
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The gate electrode GE may be formed in the dielectric layer 42 and the dielectric layer 44 and formed on the patterned barrier layer 32P′. The gate electrode GE may be electrically connected with the p-type doped III-V compound material 26P via the patterned barrier layer 32P′. The contact structure CS may penetrate through the dielectric layer 42, the dielectric layer 44, the protection layer 24, the III-V compound barrier layer 16, and a part of the III-V compound semiconductor layer 14 in the direction D1 for being electrically connected with the III-V compound semiconductor layer 14. In some embodiments, a plurality of the contact structures CS may be formed, one of the contact structures CS may be regarded as a source electrode SE in a transistor structure, and another one of the contact structures CS may be regarded as a drain electrode DE in the transistor structure, but not limited thereto. The gate electrode GE and the contact structures CS may include a barrier layer (not illustrated) and a metal layer (not illustrated) disposed on the barrier layer, but not limited thereto. In some embodiments, the gate electrode GE and the contact structure CS may further include another barrier layer disposed on the metal layer described above. The barrier layer described above may include titanium, titanium nitride, tantalum, tantalum nitride, or other suitable barrier materials, and the metal layer described above may include tungsten, copper, aluminum, titanium aluminum alloy, aluminum copper alloy, or other suitable metallic materials.
The semiconductor device 101 illustrated in
In some embodiments, the top surface 26T of the p-type doped III-V compound material 26P and the top surface 24T of the protection layer 24 may be substantially coplanar, but not limited thereto. In addition, the semiconductor device 101 may further include the substrate 10, the buffer layer 12, the dielectric layer 42, the dielectric layer 44, the isolation structure IS, the gate electrode GE, and the contact structures CS described above. The III-V compound semiconductor layer 14 is disposed on the substrate 10, and the buffer layer 12 is disposed be between the substrate 10 and the III-V compound semiconductor layer 14. The dielectric layer 42 is disposed on the patterned barrier layer 32P′, the p-type doped III-V compound material 26P, and the protection layer 24, and the dielectric layer 44 is disposed on the dielectric layer 42. The gate electrode GE is disposed on the patterned barrier layer 32P′, and the gate electrode GE is electrically connected with the p-type doped III-V compound material 26P via the patterned barrier layer 32P′. The contact structure CS penetrates through the dielectric layer 44, the dielectric layer 42, the protection layer 24, the III-V compound barrier layer 16, and a portion of the III-V compound semiconductor layer 14 in the direction D1, and the contact structure CS is electrically connected with the III-V compound semiconductor layer 14.
The following description will detail the different embodiments of the present invention. To simplify the description, identical components in each of the following embodiments are marked with identical symbols. For making it easier to understand the differences between the embodiments, the following description will detail the dissimilarities among different embodiments and the identical features will not be redundantly described.
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To summarize the above descriptions, in the semiconductor device and the manufacturing method thereof according to the present invention, the p-type doped III-V compound material may be formed in the opening penetrating through the protection layer. During the step of forming the p-type doped III-V compound material, the amount of the dopants diffused from the p-type doped III-V compound layer into the III-V compound barrier layer and/or the III-V compound semiconductor layer may be reduced by covering most of the III-V compound barrier layer with the protection layer, and the leakage current of the semiconductor device may be reduced accordingly. Additionally, during the step of forming the patterned barrier layer, the III-V compound barrier layer may be covered by the protection layer and the p-type doped III-V compound material for reducing the etching damage to the III-V compound barrier layer and/or the III-V compound semiconductor layer in the related etching processes. The electrical performance of the semiconductor device may be improved accordingly. For example, the drain current (Ids) of the semiconductor device may be enhanced because the concentration of two-dimensional electron gas (2DEG) is increased according, but not limited thereto.
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.
Number | Date | Country | Kind |
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111129169 | Aug 2022 | TW | national |