Method for removal of bulk metal contamination from III-V semiconductor substrates
View Patent ↗The invention provides a single-step method for removing bulk metal contamination from III-V semiconductor substrates. The method comprises immersing a metal contaminated III-V semiconductor substrate in a mixture of sulfuric acid and peroxide with a volume ratio of sulfuric acid to peroxide (e.g., hydrogen peroxide) between about 3:1 and about 9:1. After treating the III-V semiconductor substrates with the sulfuric acid-peroxide mixture, the bulk metal contamination may be substantially removed from the substrate while a surface roughness of the substrate after treatment of below about 0.5 nm RMS (2 μm×2 μm) is obtained. The invention further provides a method for manufacturing a semiconductor device by removing bulk metal contamination according to the single-step method of the invention before performing processing steps for forming the semiconductor device.
1. A method for removing bulk metal contamination from a III-V semiconductor substrate, the method comprising:
immersing a contaminated III-V semiconductor substrate in a mixture consisting of sulfuric acid and peroxide, wherein the sulfuric acid is a 96 wt % aqueous solution of sulfuric acid, and wherein the peroxide is a 30 wt % aqueous solution of hydrogen peroxide,
wherein a volume ratio of sulfuric acid to peroxide in the mixture consisting of sulfuric acid and peroxide is between about 3:1 and about 9:1, and wherein the III-V semiconductor substrate comprises a material selected from the group consisting of GaAs, GaP, GaSb, InAs, InP, InSb, and combinations thereof.
2. The method according to claim 1 , wherein the volume ratio of sulfuric acid to peroxide in the mixture consisting of sulfuric acid and peroxide is between about 4:1 and about 6:1.
3. The method according to claim 1 , wherein the volume ratio of sulfuric acid to peroxide in the mixture consisting of sulfuric acid and peroxide is about 4:1.
4. The method of claim 1 , wherein the mixture of sulfuric acid and peroxide has an etch rate between about 2 μm/min and about 6 μm/min.
5. The method of claim 1 , further comprising stirring the mixture consisting of sulfuric acid and peroxide during immersion of the contaminated III-V semiconductor substrate in the mixture consisting of sulfuric acid and peroxide.
6. The method of claim 1 , further comprising mechanically agitating the mixture consisting of sulfuric acid and peroxide during immersion of the contaminated III-V semiconductor substrate in the mixture consisting of sulfuric acid and peroxide.
7. The method of claim 1 , wherein the mixture consisting of sulfuric acid and peroxide has a temperature of between about 45° C. and about 95° C.
8. The method of claim 7 , wherein the mixture consisting of sulfuric acid and peroxide has a temperature of between about 80° C. and about 95° C.
9. The method of claim 1 , further comprising, before immersing the contaminated III-V semiconductor substrate in the mixture consisting of sulfuric acid and peroxide, freshly preparing the mixture consisting of sulfuric acid and peroxide, wherein freshly preparing the mixture comprises: (a) preparing a freshly prepared mixture by mixing sulfuric acid and peroxide in a volume ratio of sulfuric acid to peroxide of between about 3:1 and about 9:1; and (b) while stirring, cooling down the freshly prepared mixture to obtain a homogeneous temperature distribution.
10. The method of claim 9 , wherein the III-V semiconductor substrate comprises GaAs.
11. The method of claim 1 , wherein the III-V semiconductor substrate is contaminated by a metal bulk contamination comprising a metal selected from the group consisting of Au, Ag, Pt, Cu, Fe, Ni, and Zn.
12. The method of claim 11 , wherein the metal bulk contamination comprises Cu.
13. The method of claim 1 , wherein the peroxide is hydrogen peroxide.
14. A method for manufacturing a semiconductor device, the method comprising:
before performing further processing steps to manufacture the semiconductor device: (a) providing a contaminated III-V semiconductor substrate, wherein the contaminated III-V semiconductor substrate comprises a material selected from the group consisting of GaAs, GaP, GaSb, InAs, InP, InSb, and combinations thereof; and (b) immersing the contaminated III-V semiconductor substrate in a mixture consisting essentially of sulfuric acid and peroxide, wherein a volume ratio of sulfuric acid to peroxide in the mixture comprising sulfuric acid and peroxide is between about 3:1 and about 9:1, wherein the sulfuric acid is a 96 wt % aqueous solution of sulfuric acid, and wherein the peroxide is a 30 wt % aqueous solution of hydrogen peroxide.
15. A method for removing bulk metal contamination from a III-V semiconductor substrate, the method comprising:
immersing a contaminated III-V semiconductor substrate in a mixture consisting of sulfuric acid and peroxide, wherein the sulfuric acid is a 96 wt % aqueous solution of sulfuric acid, and wherein the peroxide is a 30 wt % aqueous solution of hydrogen peroxide,
wherein a volume ratio of sulfuric acid to peroxide in the mixture comprising sulfuric acid and peroxide is between about 3:1 and about 9:1, and wherein the III-V semiconductor substrate comprises a material selected from the group consisting of GaAs, GaP, GaSb, InAs, InP, InSb, and combinations thereof.