Method for forming a two-layered polysilicon gate electrode in a semiconductor device using grain boundaries
US5441904A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 15, 1994 |
| Grant date | Aug 15, 1995 |
| Priority date | — |
| Expiry date | Nov 15, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/28061
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method is disclosed for forming a gate electrode having two polysilicon layers and a tungsten silicide layer to prevent fluorine gas diffusion along grain boundaries from penetrating into a gate oxide film. This method for forming a gate electrode is comprised of sequentially forming a gate oxide film and a first polysilicon layer on a silicon substrate, enlarging the grain size of the first polysilicon layer by heat treatment, introducing a reagent gas, either SiH.sub.4 or Si.sub.2 H.sub.6, to further adjust the grain size within said layer, forming a second polysilicon layer on the first polysilicon layer, enlarging the grain size of the second polysilicon layer by heat treatment, introducing a reagent gas, either Si.sub.2 H.sub.6 or SiH.sub.4, whichever one was not used to treat the first polysilicon layer, forming a tungsten silicide layer on the second polysilicon layer, and patterning the tungsten silicide layer, the second polysilicon layer and the first polysilicon layer by means of a mask etching process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.