Use of mask shadowing and angled implantation in fabricating asymmetrical field-effect transistors
US6566204B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 31, 2000 |
| Grant date | May 20, 2003 |
| Priority date | — |
| Expiry date | Mar 31, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D30/0212
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
To furnish an IGFET (120 or 122) with an asymmetrically doped channel zone (144 or 164), a mask (212) is provided over a semiconductor body and an overlying electrically insulated gate electrode (148P or 168P). Ions of a semiconductor dopant species are directed toward an opening (213) in the mask from two different angular orientations along paths that originate laterally beyond opposite respective opening-defined sides of the mask. The location and shape of the opening are controlled so that largely only ions impinging from one of the angular orientations enter the intended location for the channel zone. Ions impinging from the other angular orientation are shadowed by the mask from entering the channel zone location. Although the ions impinging from this other angular orientation do not significantly dope the channel zone location, they normally enter the semiconductor body elsewhere, e.g., the intended location for the channel zone of another IGFET.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.