This application claims the benefit of Taiwan application Serial No. 102104336, filed Feb. 5, 2013, the disclosure of which is incorporated by reference herein in its entirety.
The disclosure relates in general to an oxide semiconductor element structure and a manufacturing method for the same, and relates to a semiconductor element structure having a channel protective layer or a semiconductor etching barrier layer and a manufacturing method for the same.
An oxide transistor element currently available, having superior element characteristics and uniformity and applicable to large area and low temperature process, and has manufacturers' great interest in related research. Although the oxide transistor has superior element characteristics, its material system is affected by external environment and the manufacturing process. Therefore, a structure providing enhanced element characteristics and stability and a process for manufacturing the same are a prominent task for the manufacturers.
The disclosure is related to an oxide semiconductor element structure and a manufacturing method for the same. The semiconductor element or array structure has stable electrical characteristics and superior operating efficiency.
According to one embodiment, a semiconductor element structure is provided. The semiconductor element structure comprises a gate electrode, a dielectric layer, an active layer, a source, a drain and a protective layer. The active layer and the gate electrode are disposed on opposing sides of the dielectric layer. The source is disposed on the active layer. The drain is disposed on the active layer. The protective layer is disposed on the active layer. The protective layer has a hydrogen content less than or equal to 0.1 at % and a sheet resistance higher than or equal to 10̂ 10 Ohm/sq.
According to another embodiment, a semiconductor element structure is provided. The semiconductor element structure comprises a gate electrode, a dielectric layer, an active layer, a source, a drain and a protective layer. The active layer and the gate electrode are disposed on opposing sides of the dielectric layer. The source is disposed on the active layer. The drain is disposed on the active layer. The protective layer is disposed on the active layer. The protective layer has a hydrogen content less than or equal to 0.1 at % and a sheet resistance higher than or equal to 10̂ 10 Ohm/sq. The protective layer comprises NbOx, wherein 2.4<x<5.
According to an alternative embodiment, a manufacturing method of a semiconductor element structure is provided. The method comprises the following steps. A gate electrode is formed. A dielectric layer is formed. An active layer is formed. The active layer and the gate electrode are disposed on opposing sides of the dielectric layer. A source is formed on the active layer. A drain is formed on the active layer. A protective layer is formed on the active layer. The protective layer has a hydrogen content less than or equal to 0.1 at % and a sheet resistance higher than or equal to 10̂ 10 Ohm/sq.
The above and other aspects of the disclosure will become better understood with regard to the following detailed description of the non-limiting embodiment(s). The following description is made with reference to the accompanying drawings.
In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.
An active layer 108 is formed on the dielectric layer 106. The active layer 108 may comprise a Si-based material, an organic semiconductor, an oxide semiconductor, or a combination thereof. The active layer 108 comprises indium gallium zinc oxide (InGaZnO; IGZO), aluminum tin and zinc oxide (AISnZnO; ATZO), indium oxide (InOx), gallium oxide (GaOx), tin oxide (SnOx), zinc oxide (ZnO) or a combination thereof. In an embodiment, the active layer 108 comprises InxZnySnzO, wherein 0.2≦x/(x+y+z)≦0.6, 0.15≦y/(x+y+z)≦0.35, 0.2≦z/(x+y+z)≦0.5 x, y, z represent atomic ratios (at %). These conditions help to increase the electrical characteristics and operating efficiency of the semiconductor element structure. For example, the active layer 108 may be formed by patterning a semiconductor film after the semiconductor film is formed. The semiconductor film may be formed by a chemical vapor deposition method, a physical vapor deposition method, or other suitable methods. The patterning method comprises a photolithographic etching process, but is not limited thereto.
A protective layer 110 may be formed on the active layer 108 or the dielectric layer 106. In an embodiment, the protective layer 110 physically contacts the active layer 108. The protective layer 110 may have an opening 112 exposing the active layer 108. In an embodiment, the protective layer 110 which physically contacts the active layer 108 can protect semiconductor elements from being affected by external water/oxygen, atmosphere or environment factors during the manufacturing process, such that the characteristics of the semiconductor element structure can be improved.
In an embodiment, the protective layer 110 has a hydrogen content less than or equal to 0.1 at % and a sheet resistance higher than or equal to 10̂10 Ohm/sq. For example, the sheet resistance is 10̂10 Ohm/sq−10̂14 Ohm/sq or higher than 10̂14 Ohm/sq. The protective layer 110 may comprise an oxide, a nitride or a carbide of IIA-IVA, IIIB-VIIB elements, or a combination thereof. The protective layer 110 may comprise an oxide, a nitride or a carbide of silicon (Si), titanium (Ti), aluminum (Al), niobium (Nb), tantalum (Ta), hafnium (Hf), vanadium (V), yttrium (Y), molybdenum (Mo), manganese (Mn), tin (Sn) or calcium (Ca), or a combination thereof. The protective layer 110 may comprise an oxide of niobium (Nb). The protective layer 110 may comprise NbOx, NbxTiyO, NbxSiyO, or a combination thereof. NbOx satisfies a condition: 2.4<x<5. NbxTiyO satisfies conditions: 0<x/(x+y)<1, 0<y/(x+y)<1. NbxSiyO satisfies conditions: 0<x/(x+y)<1, 0<y/(x+y)<1. Besides, the protective layer 110 may be formed by TixMnyO or TixAlyO, and as the material satisfies conditions: 0<x/(x+y)<1, 0<y/(x+y)<1, it can help to increase the electrical characteristics and operating efficiency of the semiconductor element structure. In an embodiment, the protective layer 110 is formed by patterning a film formed by using a DC sputtering process. For example, the sputtering process uses 1 kW-3 kW DC power, 50 sccm-200 sccm argon (Ar), 0 sccm-50 sccm oxygen (O2) and a sputtering target material. The sputtering target material may have a resistivity of 0.1 Ω-cm˜0.000005 Ω-cm. The sputtering target material may comprise NbOx, NbxTiyO, NbxSiyO, a combination thereof, or a material system of TixMny or TixAly. NbOx satisfies a condition: 2.4<x<5. NbxTiyO satisfies conditions: 0<x/(x+y)<1, 0<y/(x+y)<1. NbxSiyO satisfies conditions: 0<x/(x+y)<1, 0<y/(x+y)<1. TixMny satisfies conditions: 0<x/(x+y)<1, 0<y/(x+y)<1. TixAly satisfies conditions: 0<x/(x+y)<1, 0<y/(x+y)<1. These conditions help to improve the electrical characteristics and operating efficiency of the semiconductor element structure. The method for patterning a film comprises photolithographic etching process but the present disclosure is not limited thereto. In an embodiment, the protective layer 110 has an advantage of being able to be patterned easily and thus can be patterned to a fine and precise feature. The method for forming the protective layer 110 is simple and stable, and is easy to control. In an embodiment, the protective layer 110 is formed by using the DC sputtering process. Quality of the coated protective layer 110 would be stable since the target material is not affected by a shift of the DC sputtering process. Since it is easier to sputter a large-sized target material by the direct current (DC) or alternating current (AC) sputtering process than in the radio frequency (RF) sputtering process, the industries are more interested in the development of the DC or AC sputtering process than in the RF sputtering process. The DC or AC sputtering process may be subjected to the resistivity of the sputtering target material. Normally, the resistance of the sputtering target material resistance is not higher than 0.5 Ω-cm, otherwise quality as well as the conformity and yield of the process film may be affected. The sputtering process can effectively reduce the hydrogen content of the process film to be lower than 0.1 at % without affecting the characteristics of the oxide semiconductor element.
A first conductive element 114 (one of the source and the drain) and a second conductive element 116 (the other of the drain and the source) are disposed in the opening 112 of the protective layer 110 and coupled to the active layer 108. The first conductive element 114 and the second conductive element 116 may be extended to an upper surface of the protective layer 110. The first conductive element 114 and the second conductive element 116 may comprise a metal such as copper, gold, silver, or other suitable materials. In an embodiment, the first conductive element 114 and the second conductive element 116 may be formed by patterning a conductive film after the conductive film is formed. The conductive film may be formed by a deposition method such as chemical vapor deposition method, a physical vapor deposition method, or other suitable methods. The patterning method comprises photolithographic etching process, but the present disclosure is not limited thereto.
In an embodiment, the semiconductor element structure of
In an embodiment, the selected material and formation method of the elements provide superior electrical characteristics and stable operation for the semiconductor element structure.
In an embodiment of the disclosure, the protective layer 310 may be a single-layer film, or a stacking structure having two or more than two layers. Besides the inorganic material system mentioned above, an organic material, an organic-inorganic mixed material, a sol-gel material system or a spin-on-glass (SOG) material system may be used. In the embodiment of the protective layer 310 formed by a multi-layer stacking structure, the first protective layer (or a portion of the protective layer 310 contacting with the active layer 308) contacting the active layer 308 (or semiconductor layer) can be realized by an inorganic film of an oxide, a nitride, or a carbide formed by using the DC or AC sputtering process, and have the sheet resistance higher than 1×10̂10 ohm/sq. If the protective layer 310 is realized by a multi-layer structure, the method for manufacturing a portion of the protective layer 310 not contacting with the active layer 308 comprises, a chemical vapor deposition (CVD) method, a physical vapor deposition (PVD) method, or a spin-coating method, but is not limited thereto.
The active layer 408 may comprise an Si-based material, an organic semiconductor, an oxide semiconductor, or a combination thereof. The active layer 408 comprises indium gallium zinc oxide (InGaZnO; IGZO), aluminum tin and zinc oxide (AISnZnO; ATZO), indium oxide (InOx), gallium oxide (GaOx), tin oxide (SnOx), zinc oxide (ZnO) or a combination thereof. In an embodiment, the active layer 408 comprises InxZnySnzO, wherein the conditions 0.2≦x/(x+y+z)≦0.6, 0.15≦y/(x+y+z)≦0.35, and 0.2≦z/(x+y+z)≦0.5 help to improve the electrical characteristics and operating efficiency of the semiconductor element structure.
In an embodiment, the protective layer 406A physically contacts the active layer 408. The protective layer 406A protects other elements from being affected by from being affected by external water/oxygen, atmosphere or environment factors during the manufacturing process, such that the characteristics of the semiconductor element structure can be improved. In the present embodiment, the protective layer 406A may have the characteristics of dielectric material. The protective layer 406A may comprise an oxide, a nitride or a carbide of IIA-IVA, IIIB-VIIB elements, or a combination thereof. The protective layer 406A may comprise an oxide, a nitride or a carbide of silicon (Si), titanium (Ti), aluminum (Al), niobium (Nb), tantalum (Ta), hafnium (Hf), vanadium (V), yttrium (Y), molybdenum (Mo), manganese (Mn), tin (Sn) or calcium (Ca), or a combination thereof. The protective layer 406A may comprise an oxide of niobium (Nb). The protective layer 406A may comprise NbOx, NbxTiyO, NbxSiyO, or a combination thereof. NbOx satisfies a condition: 2.4<x<5. NbxTiyO satisfies conditions: 0<x/(x+y)<1, 0<y/(x+y)<1. NbxSiyO satisfies conditions: 0<x/(x+y)<1, 0<y/(x+y)<1. Besides, the protective layer 406A may be formed by TixMnyO or TixAlyO, and as the material satisfies conditions: 0<x/(x+y)<1, 0<y/(x+y)<1. Those conditions can help to increase the electrical characteristics and operating efficiency of the semiconductor element structure. In an embodiment, the protective layer 406A is formed by patterning a film formed by using a DC sputtering process. For example, the sputtering process uses 1 kW-3 kW DC power, 50 sccm-200 sccm argon (Ar), 0 sccm-50 sccm oxygen (O2) and a sputtering target material. The sputtering target material may have a resistivity of 0.1 Ω-cm˜0.000005 Ω-cm. The sputtering target material may comprise NbOx, NbxTiyO, NbxSiyO, a combination thereof, or a material system of TixMny or TixAly. NbOx satisfies a condition: 2.4<x<5. NbxTiyO satisfies conditions: 0<x/(x+y)<1, 0<y/(x+y)<1. NbxSiyO satisfies conditions: 0<x/(x+y)<1, 0<y/(x+y)<1. TixMny satisfies conditions: 0<x/(x+y)<1, 0<y/(x+y)<1. TixAly satisfies conditions: 0<x/(x+y)<1, 0<y/(x+y)<1. These conditions help to improve the electrical characteristics and operating efficiency of the semiconductor element structure. The method for patterning a film comprises photolithographic etching process but the present disclosure is not limited thereto. In an embodiment, the protective layer 406A has an advantage of being able to be patterned easily and thus can be patterned to a fine and precise feature. The method for forming the protective layer 406A is simple and stable, and is easy to control. In an embodiment, the protective layer 406A is formed by using the DC sputtering process. Quality of the coated protective layer 406A would be stable since the target material is not affected by a shift of the DC sputtering process. Moreover, the sputtering process can effectively reduce the hydrogen content of the process film to be lower than 0.1 at %, and thus characteristics of the oxide semiconductor element would not be affected by it and the semiconductor element structure has stable and outstanding operating efficiency.
In an embodiment, the semiconductor element structure of
The protective layer 406A and the dielectric layer 406B are used as a gate dielectric layer. The first conductive element 414 and the second conductive element 416 are respectively used as a source conductive element and a drain conductive element.
In comparison example 2, a SiO2 film formed by using the PECVD process is used as a protective layer. During the PECVD process of forming an SiO2 protective layer, the hydrogen plasma generated by the reaction gas makes the hydrogen atoms or ions diffuse and generate defects in the oxide semiconductor. As a result, the oxide semiconductor may be unstable in the long-term stress test, and such defects can hardly be improved in the subsequent tempering process. The excessive hydrogen content generated during the manufacturing process will make the oxide semiconductor be doped with excessive hydrogen atoms or ions, such that the oxide semiconductor film will change its characteristics from being a semiconductor, to a near conductor, and the oxide thin film transistor element will be incapacitated. Therefore, the PECVD process of forming a SiO2 protective layer has a narrow range of parameters, and it is not easy to keep the device quality stable. In general, the SiO2 film formed by using the PECVD process and used as a protective layer has a hydrogen content about 1-4 at. %. In embodiment 1, the protective layer, formed by using the sputtering process and having a hydrogen content less than or equal to 0.1 at %, protects the semiconductor element and has a reduced influence on the characteristics of the oxide semiconductor. In comparison example 3, since the oxide semiconductor element not covered by any protective layers reacts with the water vapor, oxygen and hydrogen during the long-term stress test and become defected, element characteristics decay fast.
In the embodiments illustrated in
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.
Number | Date | Country | Kind |
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102104336 | Feb 2013 | TW | national |