Dielectrically isolated well structures
US5789793A · kind A · utility
Inventors
Key dates
| Filing date | Mar 20, 1997 |
| Grant date | Aug 4, 1998 |
| Priority date | — |
| Expiry date | Mar 20, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76283
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method for fabricating a semiconductor device comprising fabricating a sacrificial wafer having a substrate wafer which includes a diffused layer and one or two epi layers. The sacrificial wafer is fusion bonded to a separately fabricated carrier/handle wafer having a layer of oxide on its surface, to form a composite wafer. Selective regions of the composite wafer are anodized and oxidized to form a plurality of wells separated from each other by a dielectric insulating layer. Next, N- epi regions above P+ epi regions are removed or alternatively, P+ diffused layers are removed from above an N- epi layer in selected regions. Finally, P- or N- single crystal silicon is grown back to the removed regions, depending on how the regions were removed. If N- single crystal is grown back to the removed regions, a high temperature drive-in is employed to finish the processing. The final structure contains N and P regions which are dielectrically isolated from each other and from the substrate. The isolated well structure can now be used to house circuit elements such as resistors, diodes, transistors, scrs, etc., individually or multiply as desired.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.