Method of manufacturing a semiconductor substrate having a cavity
The present invention provides a method of fabricating a semiconductor substrate, the method including forming a first semiconductor layer on a substrate, forming a metallic material layer on the first semiconductor layer, forming a second semiconductor layer on the first semiconductor layer and the metallic material layer, etching the substrate using a solution to remove the metallic material layer and a portion of the first semiconductor layer, and forming a cavity in the first semiconductor layer under where the metallic material layer was removed.
1. A method of fabricating a nitride semiconductor substrate, the method comprising:
forming a first nitride semiconductor layer on a substrate;
forming a metallic material layer on the first nitride semiconductor layer;
forming a second nitride semiconductor layer on the first nitride semiconductor layer and the metallic material layer, wherein a hole is formed in the metallic material layer and a first cavity is formed in the first nitride semiconductor layer under the metallic material layer during formation of the second nitride semiconductor layer;
etching the substrate using a solution to remove the metallic material layer and a portion of the first nitride semiconductor layer after forming the second nitride semiconductor layer;
forming a third nitride semiconductor layer on the second nitride semiconductor layer; and
forming a second cavity in the first nitride semiconductor layer under where the metallic material layer was removed.
2. The method of claim 1 , wherein the solution comprises potassium hydroxide (KOH).
3. The method of claim 2 , wherein the solution comprising KOH is heated to 200° C.
4. The method of claim 1 , wherein the solution comprises sodium hydroxide (NaOH).
5. The method of claim 4 , wherein the solution comprising NaOH is heated to 300° C.
6. The method of claim 1 , wherein after the metallic material layer and the portion of the first nitride semiconductor layer is removed, the substrate comprises an irregular surface.
7. The method of claim 6 , wherein the irregular surface comprises an unetched portion of the first nitride semiconductor layer and the second cavity.
8. The method of claim 1 , wherein the surface of the third nitride semiconductor layer is formed to be substantially flat.
9. A method of fabricating a nitride semiconductor substrate, the method comprising:
forming a first nitride semiconductor layer on a substrate;
forming a metallic material layer on the first nitride semiconductor layer;
forming a second nitride semiconductor layer on the first nitride semiconductor layer and the metallic material layer, wherein a hole is formed in the metallic material layer and a first cavity is formed in the first nitride semiconductor layer under the metallic material layer during formation of the second nitride semiconductor layer;
dipping the substrate in a solution to remove the metallic material layer and a portion of the first nitride semiconductor layer after forming the second nitride semiconductor layer;
forming a third nitride semiconductor layer on the second nitride semiconductor layer; and
forming a second cavity in the first nitride semiconductor layer under where the metallic material layer was removed.
10. The method of claim 9 , wherein the solution comprises hydrogen fluoride (HF).
11. The method of claim 10 , wherein the solution comprises 50% HF.
12. The method of claim 9 , wherein after the metallic material layer and the portion of the first nitride semiconductor layer is removed, the substrate comprises an irregular surface.
13. The method of claim 12 , wherein the irregular surface comprises an unetched portion of the first nitride semiconductor layer and the second cavity.
14. The method of claim 9 , wherein the surface of the third nitride semiconductor layer is formed to be substantially flat.