Contoured-tub fermi-threshold field effect transistor and method of forming same
US5543654A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 7, 1994 |
| Grant date | Aug 6, 1996 |
| Priority date | — |
| Expiry date | Dec 7, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D62/378
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A Fermi-threshold field effect transistor includes a contoured-tub region of the same conductivity type as the source, drain and channel regions and having nonuniform tub depth. The contoured-tub is preferably deeper under the source and/or drain regions than under the channel region. Thus, the tub-substrate junction is deeper under the source and/or drain regions than under the channel region. The diffusion capacitance is thereby reduced compared to a tub having a uniform tub depth, so that a high saturation current is produced at low voltages. The contoured-tub may be formed by an additional implant into the substrate using the gate as a mask.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.