Trench gate structure and method of forming a trench gate structure
US11456367B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 28, 2021 |
| Grant date | Sep 27, 2022 |
| Priority date | — |
| Expiry date | Jun 1, 2041 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D64/518
Abstract
The present invention provides a trench gate structure and a method of forming the same. The method comprises steps of forming a first trench on the surface of a substrate, a surface of a bottom of the first trench comprising a crystal face belonging to the first family of crystal faces, and a surface of a sidewall of the first trench comprising another crystal face belonging to a second family of crystal faces. With a face-selective wet etching, a specific crystal face is presented on the surface of the bottom of the trench and a thicker gate oxide layer is formed thereon after performing thermal oxidation to avoid from failure due to thinner gate oxide layer on the surface of the bottom, increase breakdown voltage, and improve reliability of the device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.