Method for making semiconductor device having field limiting ring
US5672528A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 22, 1996 |
| Grant date | Sep 30, 1997 |
| Priority date | — |
| Expiry date | Apr 22, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S148/044
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A semiconductor device characterized by a field limiting ring formed by a number of field limiting cells that define wells which are laterally diffused to form a continuous equipotential ring between interior and exterior regions of a semiconductor device. A number of active cells are formed in the interior region, and are therefore delineated from the exterior region of the device. Each of these active cells is a transistor, and preferably a field-effect transistor, whose structure is essentially identical to the field limiting cells, except that their wells are not merged but instead are isolated from each other. The field limiting ring increases the breakdown voltage and the ruggedness of device, and therefore enables the device to sustain high voltages when the device is in the off-state. The process does not require masking, implanting and diffusion steps for the sole purpose of forming the field limiting ring, but is instead fully integrated with the semiconductor process for forming the active cells. The field limiting cells also contribute to forward current conduction when the device is in the on-state, thereby lowering the on-resistance of the device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.