Heat treating nitrogen implanted gate electrode layer for improved gate electrode etch profile
US5879975A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 5, 1997 |
| Grant date | Mar 9, 1999 |
| Priority date | — |
| Expiry date | Sep 5, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/32137
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
The etch profile of side surfaces of a gate electrode is improved by heat treating the gate electrode layer after nitrogen implantation and before etching to form the gate electrode. Nitrogen implantation at high dosages to prevent subsequent impurity penetration through the gate dielectric layer, e.g., B penetration, amorphizes the upper portion of the gate electrode layer resulting in concave side surfaces upon etching to form the gate electrode. Heat treatment performed after nitrogen implantation can restore sufficient crystallinity so that, after etching the gate electrode layer, the side surfaces of the resulting gate electrode are substantially parallel.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.