Method for forming self aligned polysilicon contact
US5879997A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 30, 1991 |
| Grant date | Mar 9, 1999 |
| Priority date | — |
| Expiry date | May 30, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D64/259
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A gate contact to a field effect transistor is opened over the source/drain region by forming polysilicon plugs between the gate structure, which has a nitride top layer, and the field oxide regions. The contacts are formed by oxidizing and etching the gate structure and the polysilicon plugs. An oxide layer may be deposited prior to the etching. The latter step opens a gate contact but does not expose the silicon in the plug because the different oxidation rates of the polysilicon plug and the material on top of the gate structure create oxide layers having different thicknesses. The nitride is now removed and contacts formed to the gate structure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.