Method for fabricating semiconductor device
View Patent ↗A method for fabricating a semiconductor device includes: forming a GaN-based semiconductor layer on a substrate; forming a gate insulating film of aluminum oxide on the GaN-based semiconductor layer at a temperature equal to or lower than 450° C.; forming a protection film on an upper surface of the gate insulating film; performing a process with an alkaline solution in a state in which the upper surface of the gate insulating film is covered with the protection film; and forming a gate electrode on the gate insulating film.
1. A method for fabricating a semiconductor device comprising:
forming a GaN-based semiconductor layer on a substrate;
forming a gate insulating film of aluminum oxide on the GaN-based semiconductor layer at a temperature equal to or lower than 450° C.;
forming a protection film on an upper surface of the gate insulating film;
performing a process with an alkaline solution in a state in which the upper surface of the gate insulating film is covered with the protection film; and
forming a gate electrode on the protection film.
2. The method as claimed in claim 1 , wherein the protection film comprises any of silicon oxide, silicon oxynitride, hafnium oxide and zirconium oxide.
3. The method as claimed in claim 1 , wherein the forming of the gate electrode uses any of an ALD process, a sputtering process and a CVD process.
4. The method as claimed in claim 1 , wherein the process with the alkaline solution is performed after the gate electrode is formed.
5. The method as claimed in claim 1 , further comprising forming a source electrode and a drain electrode on the GaN-based semiconductor layer.
6. The method as claimed in claim 1 , further comprising forming a source electrode on a surface of the GaN-based semiconductor layer and a drain electrode on the substrate that contacts another surface of the GaN-based semiconductor layer opposite to said surface.
7. A method for fabricating a semiconductor device comprising:
forming a GaN-based semiconductor layer on a substrate;
forming a gate insulating film of aluminum oxide on the GaN-based semiconductor layer at a temperature equal to or lower than 450° C.;
annealing the gate insulating film at a temperature equal to or higher than a growing temperature of the gate insulating film;
performing a process with an alkaline solution after the annealing;
forming a gate electrode on the gate insulating film, and
forming a source electrode on a surface of the GaN-based semiconductor layer and a drain electrode on the substrate that contacts another surface of the GaN-based semiconductor layer opposite to said surface.
8. The method as claimed in claim 7 , wherein the temperature in the annealing is equal to higher than 700° C.
9. The method as claimed in claim 7 , wherein the forming of the gate electrode uses any of an ALD process, a sputtering process and a CVD process.
10. The method as claimed in claim 7 , wherein the process with the alkaline solution is performed after the gate electrode is formed.
11. The method as claimed in claim 7 , further comprising forming a source electrode and a drain electrode on the GaN-based semiconductor layer.
12. A method for fabricating a semiconductor device comprising:
forming a GaN-based semiconductor layer on a substrate;
forming a gate insulating film of aluminum oxide on the GaN-based semiconductor layer at a temperature equal to or lower than 450° C.;
performing a plasma process for the gate insulating film with O 2 or N 2 ;
performing a process with an alkaline solution after the plasma process; and
forming a gate electrode on the gate insulating film,
wherein the process with the alkaline solution is performed after the gate electrode is formed.
13. The method as claimed in claim 12 , wherein the forming of the gate electrode uses any of an ALD process, a sputtering process and a CVD process.
14. The method as claimed in claim 12 , further comprising forming a source electrode and a drain electrode on the GaN-based semiconductor layer.
15. The method as claimed in claim 12 , wherein a period of time for the plasma process is five minutes or longer.
16. A method for fabricating a semiconductor device comprising:
forming a GaN-based semiconductor layer on a substrate;
forming a gate insulating film of aluminum oxide on the GaN-based semiconductor layer at a temperature equal to or lower than 450° C.;
performing a plasma process for the gate insulating film with O 2 or N 2 ;
performing a process with an alkaline solution after the plasma process; and
forming a gate electrode on the gate insulating film,
forming a source electrode on a surface of the GaN-based semiconductor layer and a drain electrode on the substrate that contacts another surface of the GaN-based semiconductor layer opposite to said surface.
17. The method as claimed in claim 16 , wherein the forming of the gate electrode uses any of an ALD process, a sputtering process and a CVD process.
18. The method as claimed in claim 16 , wherein a period of time for the plasma process is five minutes or longer.