Method for tuning a work function for MOSFET gate electrodes
US6790731B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 6, 2002 |
| Grant date | Sep 14, 2004 |
| Priority date | — |
| Expiry date | Feb 6, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D84/83
Abstract
A method for creating insulated gate field effect transistors having gate electrodes with at least two layers of materials to provide gate electrode work function values that are similar to those of doped polysilicon, to eliminate the poly depletion effect, and to substantially prevent impurity diffusion into the gate dielectric. Depositing bi-layer stacks of relatively thick Al and thin TiN for n-channel FETs and bi-layer stacks of relatively thick Pd and thin TiN, or relatively thick Pd and thin TaN for p-channel FETs is disclosed. Varying the thickness of the thin TiN or TaN layers between a first and second critical thickness may be used to modulate the work function of the gate electrode and thereby obtain the desired trade-off between channel doping and drive currents in FETs.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.