Trench MOS gate device
US5770878A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 10, 1996 |
| Grant date | Jun 23, 1998 |
| Priority date | — |
| Expiry date | Apr 10, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D64/681
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
The present invention is directed to an improved trench MOS gate device that comprises a trench whose floor and sidewalls include layers of dielectric material, the layers each having a controlled thickness dimension. These thickness dimensions are related by a controlled floor to sidewall layer thickness ratio, which is established by individually controlling the thickness of each of the floor and sidewall dielectric layers. This floor to sidewall layer thickness ratio is preferably at least 1 to 1, more preferably at least 1.2 to 1. Further in accordance with the present invention, a process for forming an improved trench MOS gate device comprises etching a trench in a silicon device wafer and forming layers of dielectric material on the trench floor and on the sidewalls, each layer having a controlled thickness dimension. The thickness dimensions are related by a controlled floor to sidewall layer thickness ratio that is preferably at least 1 to 1. When silicon dioxide is employed as the dielectric material, the layers preferably comprise a composite of thermally grown and deposited silicon dioxide. The trench containing the dielectric layers is filled with polysilicon, and an i…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.