Nitridation of SIMOX buried oxide
US5468657A · kind A · utility
Assignees
Inventor
Key dates
| Filing date | Jun 17, 1994 |
| Grant date | Nov 21, 1995 |
| Priority date | — |
| Expiry date | Jun 17, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S438/98
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method is provided for improving the electrical isolation between surface regions and underlying support regions in SIMOX buried oxide wafers. The method implants nitrogen ions into a wafer to approximately the same depth as oxygen ions are implanted during SIMOX processing. A subsequent heating step causes the nitrogen ions to migrate to the interface region between the buried oxide and the upper and lower semiconductor regions of the substrate. The nitrogen passivates the interface regions to reduce the presence of buried free electrons trapped in the substrate. Nitrogen implantation can be performed before, during, or after the oxygen is implanted. Nitrogen ions can also be implanted after the SIMOX buried silicon dioxide layer has been formed. If the latter alternative is followed, the wafer must be subsequently heated to migrate the nitrogen ions to the interface regions within the substrate. Such subsequent heating can be performed as part of the formation of devices on the substrate. The resultant nitrogen passivated SIMOX substrate has improved electrical isolation between surface active devices and the supporting substrate. The invention also yields a substantial increas…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.