Split gate power device and its method of fabrication
US11289596B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 5, 2020 |
| Grant date | Mar 29, 2022 |
| Priority date | — |
| Expiry date | Aug 7, 2040 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D62/111
Abstract
A split gate power device is disclosed having a trench containing a U-shaped gate that, when biased above a threshold voltage, creates a conductive channel in a p-well. Below the gate is a field plate in the trench, coupled to the source electrode, for spreading the electric field along the trench to improve the breakdown voltage. The top gate poly is initially formed relatively thin so that it can be patterned using non-CMP techniques, such as dry etching or wet etching. As such, the power device can be fabricated in conventional fabs not having CMP capability. In one embodiment, the thin gate has vertical and lateral portions that create conductive vertical and lateral channels in a p-well. In another embodiment, the thin gate has only vertical portions along the trench sidewalls for minimizing surface area and gate capacitance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.