Semiconductor high-power mosfet device
US4974059A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 28, 1989 |
| Grant date | Nov 27, 1990 |
| Priority date | — |
| Expiry date | Aug 28, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D64/516
Abstract
A high power MOSFET is disclosed in which a plurality of hexagonal base regions formed in the surface of a chip receive respective hexagonal annular source regions. The base regions are relatively shallow and of relatively low conductivity material. A central portion of each of the base regions reaches the upper surface of the wafer and contacts a sheet source electrode which also contacts the source regions. The central regions of the base elements which contact the source electrode are of higher conductivity than the main base portion for a distance extending just below the depth of the source regions. The base regions are formed by ion implantation through a gate oxide which is exposed by a window in an overlying polysilicon layer. After ion implantation and driving of the base regions, an annular source region is diffused into each base, employing the same polysilicon window as an outer mask. A central oxide dot may be left in the center of each of the open windows so that the oxide is thicker at the central regions and remains in place during the diffusion of the source regions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.