NMOS source/drain doping with both P and As
US5021851A · kind A · utility
30Cited by
5References
11Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 13, 1989 |
| Grant date | Jun 4, 1991 |
| Priority date | — |
| Expiry date | Dec 13, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S257/917
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A process for forming N-channel MOS sources and drains, by implanting both phosphorus and arsenic. The high diffusivity of phosphorus causes it to diffuse in advance of the bulk of the arsenic, so that, after annealing, the source/drain regions have graded regions of gradually decreasing conductivity adjacent to the end of the channels. Thus the electric potential gradient at the ends of the channels is reduced, and impact ionization and hot carrier effects are avoided. The effective radius of the source (or drain) junction is increased, providing increased breakdown voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.