Nitrogen oxidation to reduce encroachment
View Patent ↗A method of manufacturing a metal oxide semiconductor. A gate structure of the metal oxide semiconductor is etched. A nitrogen-comprising gas, which may be NO or N 2 O, is made to flow over the metal oxide semiconductor. A pre-implant film is grown over the edges of the gate structure. The pre-implant film may repair damage to a gate stack edge caused by an etching process. The film may be substantially silicon nitride. Beneficially, such a film may be thinner than a conventional silica oxide film. A thinner film does not deleteriously contribute to non-uniformities in a tunnel oxide. A non-uniform tunnel oxide may result in a non-uniform field between a gate and a channel. Non-uniform fields may have numerous deleterious effects. Advantageously, embodiments of the present invention overcome prior art deficiencies in repairing gate stack edge defects. In this novel manner, gate stack edge defects may be physically repaired without deleterious consequences to the electrical behavior of a metal oxide semiconductor device. The novel application of silicon nitride to this application allows thin repair layers to be grown. Advantageously, semiconductors manufactured using embodiments of the present invention may utilize smaller process feature sizes, resulting in denser arrays of semiconductor devices, resulting in lower costs for such devices and realizing a competitive advantage to practitioners of the improvements in the arts herein described.
1. A method of manufacturing a metal oxide semiconductor comprising:
etching a gate structure of said metal oxide semiconductor;
flowing a nitrogen-comprising gas over said metal oxide semiconductor; and
growing a pre-implant film over edges of said gate structure.
2. The method of manufacturing a metal oxide semiconductor as described in claim 1 wherein said pre-implant film is less than 60 angstroms thick.
3. The method of manufacturing a metal oxide semiconductor as described in claim 1 wherein said nitrogen-comprising gas is substantially NO.
4. The method of manufacturing a metal oxide semiconductor as described in claim 1 wherein said nitrogen-comprising gas is substantially N 2 O.
5. The method of manufacturing a metal oxide semiconductor as described in claim 1 further comprising implanting a source region subsequent to said growing.
6. The method of manufacturing a metal oxide semiconductor as described in claim 1 wherein said pre-implant film comprises nitrogen.
7. The method of manufacturing a metal oxide semiconductor as described in claim 6 wherein said pre-implant film is substantially silicon nitride.
8. A method of repairing edge defects in a gate stack comprising:
placing a wafer comprising semiconductors with gate stack edge defects into an oven;
flowing a nitrogen-comprising gas over said gate stack; and
growing a pre-implant film over edges of said gate structure to repair said edge defects.
9. The method of repairing edge defects in a gate stack as described in claim 8 wherein said pre-implant film is less than 60 angstroms thick.
10. The method of repairing edge defects in a gate stack as described in claim 8 wherein said nitrogen-comprising gas is substantially NO.
11. The method of repairing edge defects in a gate stack as described in claim 8 wherein said nitrogen-comprising gas is substantially N 2 O.
12. The method of repairing edge defects in a gate stack in claim 8 further comprising implanting a source region subsequent to said growing.
13. The method of repairing edge defects in a gate stack as described in claim 8 wherein said pre-implant film comprises nitrogen.
14. The method of manufacturing a metal oxide semiconductor as described in claim 13 wherein said pre-implant film is substantially silicon nitride.