Method of forming a split poly-SiGe/poly-Si alloy gate stack
US7465649B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 30, 2007 |
| Grant date | Dec 16, 2008 |
| Priority date | — |
| Expiry date | Aug 30, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D84/038
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A multi-layered gate electrode stack structure of a field effect transistor device is formed on a silicon nano crystal seed layer on the gate dielectric. The small grain size of the silicon nano crystal layer allows for deposition of a uniform and continuous layer of poly-SiGe with a [Ge] of up to at least 70% using in situ rapid thermal chemical vapor deposition (RTCVD). An in-situ purge of the deposition chamber in a oxygen ambient at rapidly reduced temperatures results in a thin SiO2 or SixGeyOz interfacial layer of 3 to 4 A thick. The thin SiO2 or SixGeyOz interfacial layer is sufficiently thin and discontinuous to offer little resistance to gate current flow yet has sufficient [O] to effectively block upward Ge diffusion during heat treatment to thereby allow silicidation of the subsequently deposited layer of cobalt. The gate electrode stack structure is used for both nFETs and pFETs.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.