Method and system for doping control in gallium nitride based devices
View Patent ↗A method of growing a III-nitride-based epitaxial structure is disclosed. The method includes forming a GaN-based drift layer coupled to the GaN-based substrate, where forming the GaN-based drift layer comprises doping the drift layer with indium to cause the indium concentration of the drift layer to be less than about 1×10 16 cm −3 and to cause the carbon concentration of the drift layer to be less than about 1×10 16 cm −3 . The method also includes forming an n-type channel layer coupled to the GaN-based drift layer, forming an n-contact layer coupled to the GaN-based drift layer, and forming a second electrical contact electrically coupled to the n-contact layer.
1. A vertical JFET formed by a method comprising:
providing a GaN-based substrate having a surface and a first electrical contact opposing the surface;
forming a GaN-based drift layer coupled to the GaN-based substrate and operable to conduct current in a direction substantially orthogonal to the surface, wherein forming the GaN-based drift layer comprises doping the drift layer with indium to cause the indium concentration of the drift layer to be less than about 1×10 16 cm −3 and to cause the carbon concentration of the drift layer to be less than about 1×10 16 cm −3 ; forming an n-type channel layer coupled to the GaN-based drift layer;
forming an n-contact layer coupled to the GaN-based drift layer and substantially parallel to the surface;
forming a second electrical contact electrically coupled to the n-contact layer;
forming a p-type gate region electrically coupled to the n-type channel layer; and
forming a third electrical contact electrically coupled to the p-type gate region.
2. The vertical JFET of claim 1 , wherein a concentration of indium in the n-type drift layer is between 1×10 15 cm −3 and 1×10 16 cm −3 .
3. The vertical JFET of claim 1 , wherein a thickness of the n-type drift layer is greater than 1 μm.
4. The vertical JFET of claim 1 , wherein the n-type channel layer comprises a GaN layer.
5. The vertical JFET of claim 1 , wherein the n-type drift layer comprises an n-type GaN layer.
6. The vertical JFET of claim 1 , wherein the GaN-based drift layer is formed by a metal organic chemical vapor deposition (MOCVD) process.
7. The vertical JFET of claim 6 , wherein during the MOCVD process, a metalorganic precursor is used.
8. The vertical JFET of claim 1 , wherein the GaN-based drift layer is formed in an environment containing at least one of tri-methyl indium (TMI), tri-ethyl indium (TEI), and ethyldimethylindium (EDMI).
9. The vertical JFET of claim 1 , wherein the GaN-based drift layer is formed in an environment containing hydrogen.
10. The vertical JFET of claim 1 , wherein the GaN-based drift layer is formed at a temperature greater than 1000° C.
11. A method of manufacturing a vertical JFET, the method comprising:
providing a GaN-based substrate having a surface and a first electrical contact opposing the surface;
forming a GaN-based drift layer coupled to the GaN-based substrate and operable to conduct current in a direction substantially orthogonal to the surface, wherein forming the GaN-based drift layer comprises doping the drift layer with indium to cause the indium concentration of the drift layer to be less than about 1×10 16 cm −3 and to cause the carbon concentration of the drift layer to be less than about 1×10 16 cm −3 ; forming an n-type channel layer coupled to the GaN-based drift layer;
forming an n-contact layer coupled to the GaN-based drift layer and substantially parallel to the surface;
forming a second electrical contact electrically coupled to the n-contact layer;
forming a p-type gate region electrically coupled to the n-type channel layer; and
forming a third electrical contact electrically coupled to the p-type gate region.
12. The method of claim 11 , wherein a concentration of indium in the n-type drift layer is between 1×10 15 cm −3 and 1×10 16 cm −3 .
13. The method of claim 11 , wherein a thickness of the n-type drift layer is greater than 1 μm.
14. The method of claim 11 , wherein the n-type channel layer comprises a GaN layer.
15. The method of claim 11 , wherein the n-type drift layer comprises an n-type GaN layer.
16. The method of claim 11 , wherein the GaN-based drift layer is formed by metal a metal organic chemical vapor deposition (MOCVD) process.
17. The method of claim 16 , wherein during the MOCVD process, a metalorganic precursor is used.
18. The method of claim 11 , wherein the GaN-based drift layer is formed in an environment containing at least one of tri-methyl indium (TMI), tri-ethyl indium (TEI), and ethyldimethylindium (EDMI).
19. The method of claim 11 , wherein the GaN-based drift layer is formed in an environment containing hydrogen.
20. The method of claim 11 , wherein the GaN-based drift layer is formed at a temperature greater than 1000° C.