Methods for selective dry etching gallium oxide

Patent metadata

Field	Value
Publication number	US-11942330-B2
Application number	US-202217836694-A
Country	US
Kind code	B2
Filing date	Jun 9, 2022
Priority date	Sep 8, 2020
Publication date	Mar 26, 2024
Grant date	Mar 26, 2024

Abstract

Exemplary methods of etching gallium oxide from a semiconductor substrate may include flowing a first reagent in a substrate processing region housing the semiconductor substrate. The first reagent may include HX. X may be at least one of fluorine, chlorine, and bromine. The semiconductor substrate may include an exposed region of gallium oxide. Fluorinating the exposed region of gallium oxide may form a gallium halide and H 2 O. The methods may include flowing a second reagent in the substrate processing region. The second reagent may be at least one of trimethylgallium, tin acetylacetonate, tetramethylsilane, and trimethyltin chloride. The second reagent may promote a ligand exchange where a methyl group may be transferred to the gallium halide to form a volatile Me 2 GaY or Me 3 Ga. Y may be at least one of fluorine, chlorine, and bromine from the second reagent. The methods may include recessing a surface of the gallium oxide.

First claim

The invention claimed is:

1. A method of etching gallium oxide from a semiconductor substrate, the method comprising:
flowing a first reagent in a substrate processing region housing the semiconductor substrate, wherein the first reagent comprises HX, wherein H is hydrogen, wherein X is at least one of fluorine, chlorine, and bromine, and wherein the semiconductor substrate comprises an exposed region of gallium oxide overlying gallium nitride, and fluorinating the exposed region of gallium oxide to form a gallium halide and H 2 O;
flowing a second reagent in the substrate processing region, wherein the second reagent is at least one of trimethylgallium, tin acetylacetonate, tetramethylsilane, and trimethyltin chloride, the second reagent promoting a ligand exchange wherein a methyl group is transferred to the gallium halide to form a volatile Me 2 GaY or Me 3 Ga, wherein Me is methyl, and wherein Y is at least one of fluorine, chlorine, and bromine from the second reagent;
flowing a third reagent in the substrate processing region, wherein the third reagent is at least one of chlorine, bromine, boron trichloride, and boron tribromide; and
recessing a surface of the gallium oxide.

2. The method of claim 1 , wherein at least one of flowing the first reagent and flowing the second reagent includes pulsing for about 3 seconds.

3. The method of claim 1 , wherein subsequent to at least one of flowing the first reagent and flowing the second reagent includes purging the substrate processing region with an inert gas.

4. The method of claim 3 , wherein subsequent to flowing the first reagent, the substrate processing region is purged with an inert gas to remove the H 2 O.

5. The method of claim 3 , wherein the inert gas comprises He, Ar, or diatomic nitrogen.

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

7. The method of claim 6 , wherein the method demonstrates an etching rate of from about 0.1 Å to about 6 Å per cycle.

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

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

10. The method of claim 1 , wherein the first reagent comprises HF.

11. A method of etching gallium oxide from a semiconductor substrate, the method comprising:
flowing a first reagent in a substrate processing region housing the semiconductor substrate, wherein the first reagent comprises MeX, wherein X is at least one of fluorine, chlorine, and bromine, wherein Me comprises at least one of titanium, niobium, tantalum, molybdenum, tungsten, or sulfur, and wherein the semiconductor substrate comprises an exposed region of gallium oxide, and fluorinating the exposed region of gallium oxide to form a gallium halide and H 2 O;
flowing a second reagent in the substrate processing region, wherein the second reagent is at least one of trimethylgallium, aluminum chloride, tin tetrachloride, tin acetylacetonate, tetramethylsilane, trimethyltin chloride, and boron tribromide, the second reagent promoting a ligand exchange, wherein the ligand exchange forms a volatile; and
recessing a surface of the gallium oxide, wherein an etching selectivity between gallium oxide and gallium nitride is greater than or about 10:1.

12. The method of claim 11 , wherein subsequent to at least one of flowing the first reagent and flowing the second reagent includes purging the substrate processing region with an inert gas.

13. The method of claim 11 , wherein the recessing the surface of the gallium oxide is self-limiting.

14. The method of claim 11 , further comprising:
subsequent to flowing the first reagent, purging the substrate processing region with an inert gas, wherein the purging removes the H 2 O.

15. The method of claim 11 , wherein a temperature in the substrate processing region is maintained at between about 150° C. and about 650° C.

16. The method of claim 11 , wherein a pressure in the substrate processing region is maintained at less than or about 250 Torr.

17. The method of claim 11 , wherein an etching selectivity between gallium oxide and gallium nitride is greater than or about 20:1.

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