Method of forming a SIMOX structure
US5310689A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 2, 1990 |
| Grant date | May 10, 1994 |
| Priority date | — |
| Expiry date | Apr 2, 2010 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S438/909
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A SIMOX structure having a reduced number of defects is formed by performing a two step anneal. In one embodiment, a conventional anneal is followed by an H.sub.2 /Si anneal. The conventional anneal first densifies the buried oxide layer in order to make the oxide less reactive with hydrogen. The H.sub.2 /Si anneal forms a quasi-equilibrium at the superficial semiconductor layer surface, thus there is no etching of the silicon surface and there is only a negligible amount of silicon deposition. The H.sub.2 reacts with the oxide precipitates and dissolves them. In a second embodiment the two step anneal comprises a low temperature H.sub.2 anneal followed by a conventional anneal. At low temperature, H.sub.2 can diffuse through silicon, but is much less reactive. Thus, etching of the superficial silicon and silicon dioxide buried layer is minimal. The conventional anneal is at a higher temperature, thus H.sub.2 can react with the oxygen precipitates to remove them.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.