Method for in-situ dry cleaning, passivation and functionalization of Si—Ge semiconductor surfaces

Patent metadata

Field	Value
Publication number	US-9818599-B2
Application number	US-201314062136-A
Country	US
Kind code	B2
Filing date	Oct 24, 2013
Priority date	Oct 24, 2012
Publication date	Nov 14, 2017
Grant date	Nov 14, 2017

Abstract

A method for in-situ dry cleaning of a SiGe semiconductor surface doses the SiGe surface with ex-situ wet HF in a clean ambient environment or in-situ dosing with gaseous NH 4 F to remove oxygen containing contaminants. Dosing the SiGe surface with atomic H removes carbon containing contaminants. Low temperature annealing pulls the surface flat. Passivating the SiGe semiconductor surface with H 2 O 2 vapor for a sufficient time and concentration forms an a oxygen monolayer(s) of —OH sites on the SiGe. Second annealing the SiGe semiconductor surface is conducted at a temperature below that which would induce dopant diffusion. A method for in-situ dry cleaning of a SiGe semiconductor surface, ex-situ degreases the Ge containing semiconductor surface and removes organic contaminants. The surface is then dosed with HF(aq) or NH4F(g) generated via NH 3 +NH or NF 3 with H 2 or H 2 O to remove oxygen containing contaminants. In-situ dosing of the SiGe surface with atomic H removes carbon containing contaminants.

First claim

The invention claimed is:

1. A method for in-situ dry cleaning of a SiGe semiconductor surface, comprising:
dosing the SiGe surface with ex-situ wet HF in a clean ambient environment or in-situ dosing with gaseous NH 4 F;
dosing the SiGe surface with atomic H;
low temperature (below ˜550° C.) annealing to pull the SiGe surface flat;
in a vacuum chamber, passivating the SiGe semiconductor surface with H 2 O 2 vapor to form a monolayer(s) of —OH sites on the SiGe; and
in the vacuum chamber, second annealing the SiGe semiconductor surface at a temperature below ˜650° C. to avoid dopant diffusion.

2. The method of claim 1 , wherein said dosing the SiGe surface comprises dosing with HF(aq).

3. The method of claim 1 , wherein said dosing the SiGe surface with NH 4 comprises in-situ thermally mixing NH 3 +NF 3 or mixing in a plasma.

4. The method of claim 1 , wherein said dosing the SiGe surface with NH 4 comprises in-situ plasma mixing of NF 3 with H 2 or H 2 O.

5. The method of claim 1 , wherein said dosing the SiGe surface with HF comprises wet-dipping in HF/H 2 O, followed by keeping the SiGe surface in an inert atmosphere and then followed by said dosing with the SiGe surface with atomic H, conduct in-situ.

6. The method of claim 1 , wherein said low temperature annealing is conducted at or below ˜350° C.

7. The method of claim 1 , further comprising a preliminary step of degreasing the SiGe surface.

8. The method of claim 7 , wherein the degreasing comprises sonication in acetone, methanol and high performance liquid chromatography (HPLC) water.

9. The method of claim 1 , wherein the vacuum chamber comprises an atomic layer deposition (ALD) reactor.

10. The method of claim 1 , wherein SiGe semiconductor surface is SiGe(110) or SiGe(100).

11. The method of claim 1 , further comprising, in the vacuum chamber, providing a monolayer passivation and nucleation by depositing a monolayer of H 2 O 2 , followed by an anneal, followed by saturation with trimethylaluminum (TMA) and an anneal.

12. The method of claim 11 , wherein the vacuum chamber comprises an atomic layer deposition (ALD) reactor.

13. The method of claim 1 , wherein the H 2 O 2 comprises 2% vapor H 2 O 2 (g)/H 2 O(g).

14. The method of claim 1 , further comprising forming a monolayer of —OH sites with a saturation dose of H 2 O 2 (g).

15. The method of claim 14 , further comprising applying a saturation dose of trimethylaluminum (TMA) to form dimethylaluminum (DMA) bonded to the H 2 O 2 (g) saturated SiGe semiconductor surface via an Al—O—Ge/Si bond.

16. The method of claim 14 , further comprising conducting an anneal after said applying a saturation dose of trimethylaluminum (TMA) at a temperature of ˜200-300° C.

Assignees

• Univ California

Inventors

• Kaufman-Osborn Tobin
• Kummel Andrew C
• Kiantaj Kiarash

Classifications

• H10P70/18 Primary

  by combined dry cleaning and wet cleaning (H10P70/52 takes precedence) · CPC title

• H10P70/12

  by dry cleaning only (H10P70/52 takes precedence) · CPC title

• H10P50/00

  Etching of wafers, substrates or parts of devices · CPC title

• H10P14/6512

  by exposure to a gas or vapour · CPC title

• H10P14/6504

  In-situ cleaning · CPC title