Biaxial strained field effect transistor devices
US8361867B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 19, 2010 |
| Grant date | Jan 29, 2013 |
| Priority date | — |
| Expiry date | Apr 28, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/0002
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A process for forming contacts to a field effect transistor provides edge relaxation of a buried stressor layer, inducing strain in an initially relaxed surface semiconductor layer above the buried stressor layer. A process can start with a silicon or silicon-on-insulator substrate with a buried silicon germanium layer having an appropriate thickness and germanium concentration. Other stressor materials can be used. Trenches are etched through a pre-metal dielectric to the contacts of the FET. Etching extends further into the substrate, through the surface silicon layer, through the silicon germanium layer and into the substrate below the silicon germanium layer. The further etch is performed to a depth to allow for sufficient edge relaxation to induce a desired level of longitudinal strain to the surface layer of the FET. Subsequent processing forms contacts extending through the pre-metal dielectric and at least partially into the trenches within the substrate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.