Methods for selective dry etching gallium oxide

Patent metadata

Field	Value
Publication number	US-11398388-B2
Application number	US-202017014251-A
Country	US
Kind code	B2
Filing date	Sep 8, 2020
Priority date	Sep 8, 2020
Publication date	Jul 26, 2022
Grant date	Jul 26, 2022

Abstract

Exemplary methods of etching gallium oxide from a semiconductor substrate may include selectively etching gallium oxide relative to gallium nitride. The method may include flowing a reagent in a substrate processing region housing the semiconductor substrate. The reagent may include at least one of chloride and bromide. The method may further include contacting an exposed region of gallium oxide with the at least one of chloride and bromide from the reagent to form a gallium-containing gas. The gallium-containing gas may be removed by purging the substrate processing region with an inert gas. The method includes recessing a surface of the gallium oxide. The method may include repeated cycles to achieve a desired depth.

First claim

The invention claimed is:

1. A method of etching gallium oxide from a semiconductor substrate, the method comprising:
flowing a reagent in a substrate processing region housing the semiconductor substrate, wherein the reagent comprises at least one of chloride and bromide, wherein the reagent comprises titanium tetrachloride, titanium tetrabromide, silicon tetrachloride, silicon tetrabromide, vanadium(V) chloride, niobium pentachloride, tantalum pentachloride, tungsten(V) chloride, molybdenum(V) chloride, zirconium tetrachloride, molybdenum oxytetrachloride, tungsten(VI) oxytetrachloride, or combinations thereof, and wherein the semiconductor substrate comprises an exposed region of gallium oxide;
contacting the exposed region of gallium oxide with the at least one of chloride and bromide from the reagent to form a gallium-containing gas;
halting the flow of the at least one of chloride and bromide from the reagent after a first period of time, wherein the first period of time is less than or about 5 minutes;
purging the substrate processing region with an inert gas to remove the gallium-containing gas for a second period of time; and
recessing a surface of the gallium oxide.

2. The method of claim 1 , wherein the substrate processing region is maintained plasma free.

3. The method of claim 1 , wherein the reagent comprises titanium tetrachloride.

4. The method of claim 1 , wherein a temperature in the substrate processing region is maintained between about 150° C. and about 650° C.

5. The method of claim 1 , wherein a pressure in the substrate processing region is maintained at less than or about 250 Torr.

6. The method of claim 1 , wherein the inert gas comprises nitrogen, helium, argon, or combinations thereof.

7. The method of claim 1 , wherein the second period of time is greater than or about 5 seconds.

8. The method of claim 1 , wherein a temperature in the substrate processing region is maintained at between about 150° C. and about 650° C.

9. The method of claim 1 , wherein the at least one of chloride and bromide from the reagent directly contacts the exposed region of gallium oxide.

10. The method of claim 1 , wherein the method is repeated for at least two cycles to achieve a desired etch depth.

11. The method of claim 10 , wherein the recessing the surface of the gallium oxide etches a thickness of less than or about 30 A per cycle.

12. The method of claim 1 , wherein the exposed region of gallium oxide is overlying gallium nitride.

13. The method of claim 12 , wherein an etching selectivity between gallium oxide and gallium nitride is greater than or about 10:1.

Assignees

• Applied Materials Inc

Inventors

• Liu Feng Q
• Enman Lisa J
• Kalutarage Lakmal C
• Saly Mark J

Classifications

• H10P14/6939

  characterised by the metal · CPC title

• H10P50/285 Primary

  of materials not containing Si, e.g. PZT or Al2O3 · CPC title

• H10P95/70

  Chemical treatments · CPC title

• H10P52/00

  Grinding, lapping or polishing of wafers, substrates or parts of devices · CPC title

• H10P50/20 Primary

  Dry etching; Plasma etching; Reactive-ion etching · CPC title