High density trench-gated power MOSFET
US6348712B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 27, 1999 |
| Grant date | Feb 19, 2002 |
| Priority date | — |
| Expiry date | Oct 27, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D64/111
Abstract
A trench-gated power MOSFET contains a highly doped region in the body region which forms a PN junction diode with the drain at the center of the MOSFET cell. This diode has an avalanche breakdown voltage which is lower than the breakdown voltage of the drain-body junction near to the wall of the trench. Thus the MOSFET breaks down in the center of the cell avoiding the generation of hot carriers that could damage the gate oxide layer. The drain-body junction is located at a level which is above the bottom of the trench, thereby avoiding any deep diffusion that would increase the cell width and reduce the cell packing density. This compact structure is achieved by limiting the thermal budget to which the device is exposed after the body region is implanted. As a result, the body and its highly doped region do not diffuse significantly, and dopant from the highly doped region does not get into the channel region of the device so as to increase its threshold voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.