Method of fabricating MOSFET
US10957776B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | May 21, 2020 |
| Grant date | Mar 23, 2021 |
| Priority date | — |
| Expiry date | May 21, 2040 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D30/601
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method for fabricating MOSFET is disclosed. In the method, after a gate is formed by etching a deposited undoped or lightly-doped polysilicon layer, with the portions of the gate above channel edge between a channel region and STI region being protected, ions are doped into the remaining gate portion during source/drain implantation. As a result, each of the gate portions above channel edge is constructed of a doped second polysilicon layer stacked with undoped (or lightly-doped) first polysilicon layers, while the remaining gate portion is simply constituted by the doped second polysilicon layer. This can increase a threshold voltage of the MOSFET at channel edge. Optionally, before the gate is formed by etching the polysilicon, the portions of the polysilicon above the channel edge may be protected, followed by doping ions into the remaining portions of the polysilicon.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.