Technique for reducing silicide defects by reducing deleterious effects of particle bombardment prior to silicidation
View Patent ↗By reducing the effect of particle bombardment during the sequence for forming a metal silicide in semiconductor devices, the defect rate and the metal silicide uniformity may be enhanced. For this purpose, the metal may be deposited without an immediately preceding sputter etch process, wherein, in a particular embodiment, an additional oxidation process is performed to efficiently remove any silicon contaminations and surface impurities by a subsequent wet chemical treatment on the basis of HF, which is followed by the metal deposition.
1. A method, comprising:
treating a surface region of a semiconductor structure including a conductive silicon-containing surface portion by a particle bombardment;
exposing said treated surface region to an oxidizing ambient to thereby form oxidized portions on said treated surface region;
removing said oxidized portions formed on said treated surface region;
after removing said oxidized portions, forming a metal layer on said surface region; and
initiating formation of a metal silicide in said conductive silicon-containing surface portion.
2. The method of claim 1 , wherein treating said surface region of the semiconductor structure comprises treating said surface region in a sputter deposition ambient substantially without depositing a metal.
3. The method of claim 1 , wherein treating said surface region of the semiconductor structure comprises exposing said surface region to a plasma ambient comprising an inert ion species.
4. The method of claim 1 , wherein said surface region remains substantially untreated after removing said oxidized portions and prior to forming said metal layer.
5. The method of claim 1 , wherein said metal layer comprises a refractory metal.
6. The method of claim 1 , wherein said conductive silicon-containing surface portion represents a surface region of at least one of a drain region, a source region and a gate electrode of a field effect transistor.
7. The method of claim 1 , wherein removing said oxidized portions comprises performing a wet chemical etch process.
8. The method of claim 7 , wherein said wet chemical etch process is based on hydrofluoric acid (HF).
9. The method of claim 1 , further comprising forming a protective layer on said surface region prior to treating said surface region by particle bombardment.
10. The method of claim 9 , wherein said protective layer is comprised of silicon dioxide.
11. The method of claim 9 , further comprising removing said protective layer prior to treating said surface region by particle bombardment.
12. A method, comprising:
performing a silicidation pretreating process for cleaning or activating a silicon-containing region of at least one of a gate electrode, a source region and a drain region, the pretreating process including:
treating said silicon-containing region by particle bombardment on the basis of at least one inert ion species;
exposing said silicon-containing region to an oxidizing ambient after treating said silicon-containing region by particle bombardment to thereby form oxidized portions and removing said oxidized portions during said wet chemical treatment; and
performing a wet chemical treatment to remove said oxidized portions as a last reactive process prior to a silicidation process;
depositing a metal layer on said pretreated silicon-containing region; and
forming metal silicide in said silicon-containing region on the basis of said metal layer.
13. The method of claim 12 , wherein said wet chemical treatment is an etch process on the basis of hydrofluoric acid (HF).
14. The method of claim 12 , wherein said particle bombardment is performed in a sputter deposition ambient substantially without depositing material.
15. The method of claim 12 , further comprising forming a protective layer above said silicon-containing region prior to performing said silicidation pretreatment process so as to reduce contamination during handling and transport of a substrate bearing said silicon-containing region.
16. The method of claim 15 , further comprising removing said protective layer prior to performing said silicidation pretreatment process.
17. The method of claim 16 , wherein said protective layer is removed by a wet chemical etch process.
18. A method, comprising:
performing a silicidation pretreating process for cleaning or activating a silicon-containing region of at least one of a gate electrode, a source region and a drain region, the pretreating process including:
treating said silicon-containing region by particle bombardment in a sputter deposition ambient substantially without depositing material;
exposing said silicon-containing region to an oxidizing ambient after treating said silicon-containing region by particle bombardment to thereby form oxidized portions and removing said oxidized portions during said wet chemical treatment; and
performing a wet chemical treatment to remove said oxidized portions as a last reactive process prior to a silicidation process;
depositing a metal layer on said pretreated silicon-containing region; and
forming metal silicide in said silicon-containing region on the basis of said metal layer.
19. The method of claim 18 , further comprising forming a protective layer above said silicon-containing region prior to performing said silicidation pretreatment process so as to reduce contamination during handling and transport of a substrate bearing said silicon-containing region.
20. The method of claim 19 , further comprising removing said protective layer prior to performing said silicidation pretreatment process.
21. The method of claim 20 , wherein said protective layer is removed by a wet chemical etch process.