Gallium nitride materials and methods associated with the same
View Patent ↗Semiconductor materials including a gallium nitride material region and methods associated with such structures are provided. The semiconductor structures include a strain-absorbing layer formed within the structure. The strain-absorbing layer may be formed between the substrate (e.g., a silicon substrate) and an overlying layer. It may be preferable for the strain-absorbing layer to be very thin, have an amorphous structure and be formed of a silicon nitride-based material. The strain-absorbing layer may reduce the number of misfit dislocations formed in the overlying layer (e.g., a nitride-based material layer) which limits formation of other types of defects in other overlying layers (e.g., gallium nitride material region), amongst other advantages. Thus, the presence of the strain-absorbing layer may improve the quality of the gallium nitride material region which can lead to improved device performance.
1. A method of forming a semiconductor structure comprising:
providing a substrate;
forming an amorphous silicon nitride-based material layer of a different material than the substrate, the amorphous silicon nitride-based material layer formed directly on the substrate and having a uniform thickness over the entire substrate;
forming a nitride-based material overlying layer on the silicon nitride-based material layer wherein the nitride-based material overlying layer has an epitaxial relationship with said substrate and comprises an aluminum nitride-based material and/or a gallium nitride-based material;
forming a III-nitride transition layer on said overlying layer;
wherein said uniform thickness of said amorphous silicon nitride-based material layer is determined based on a thickness of said nitride-based material overlying layer.
2. The method of claim 1 , comprising providing the substrate in a reaction chamber and further comprising introducing at least a nitrogen source into the reaction chamber to form the amorphous silicon nitride-based material layer.
3. The method of claim 2 , further comprising introducing a second source into the reaction chamber to form a nitride-based material overlying layer on the silicon nitride-based material layer.
4. The method of claim 2 , further comprising introducing a silicon source into the reaction chamber to react with the nitrogen source to form the amorphous silicon nitride-based material layer.
5. The method of claim 2 , comprising introducing a nitrogen source into the reaction chamber to form an amorphous silicon nitride-based material layer in a MOCVD process.
6. The method of claim 2 , wherein the temperature in the reaction chamber is between about 1000° C. and about 1400° C. when the nitrogen source is introduced into the chamber.
7. The method of claim 2 , wherein the pressure in the reaction chamber is between about 1 torr and about 10 3 torr when the nitrogen source is introduced into the chamber.
8. The method of claim 2 , wherein the pressure in the reaction chamber is between about 20 torr and about 40 torr when the nitrogen source is introduced into the chamber.
9. The method of claim 2 , wherein the nitrogen source is ammonia.
10. The method of claim 2 , wherein the substrate is silicon and the nitrogen source reacts with the silicon substrate to form a silicon nitride-based material layer.
11. The method of claim 3 , wherein the second source comprises an aluminum source.
12. The method of claim 3 , wherein the aluminum source reacts with the nitrogen source to form a layer of aluminum nitride.
13. The method of claim 1 , wherein the substrate is silicon.
14. The method of claim 1 , wherein the substrate is silicon carbide.
15. A method of forming a semiconductor structure comprising:
providing a substrate in a reaction chamber;
introducing at least a nitrogen source into the reaction chamber to form a silicon nitride-based material layer having a uniform thickness of less than 100 Angstroms over the entire substrate in a CVD process, the silicon nitride-based material layer made of a different material than the substrate;
introducing a second source into the reaction chamber to form a single crystal nitride-based material overlying layer on the silicon nitride-based material layer, wherein the nitride-based material overlying layer comprises an aluminum nitride-based material and/or gallium nitride-based material;
utilizing a vertical growth process to form a III-nitride transition layer on said overlying layer;
wherein the uniform thickness of the silicon nitride-based material layer is determined based on a thickness of the nitride-based material overlying layer.