Method of making a semiconductor device of a high withstand voltage
US5156981A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 6, 1989 |
| Grant date | Oct 20, 1992 |
| Priority date | — |
| Expiry date | Apr 6, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/351
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Phosphorus is doped into one of the major surfaces of an n-type silicon semiconductor substrate, and boron is doped into the other major surface. Thereafter, the structure is diffused into the surface regions of the substrate at a high temperature and for a long time, so that an n-buffer layer is formed in the first major surface, and a p-base layer is formed in the second major surface. Impurity of n-type is diffused into the p-base layer, to form an n-emitter layer. Impurity of p-type is diffused into the n-buffer layer, to selectively form p-emitter layer. Further, n-type impurity is diffused into the n-buffer layer, to form n-type anode short layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.