Boron penetration through thin gate oxides in p-channel MOSFETs with heavily boron-doped gates causes undesirable positive threshold voltage shifts. P-channel MOSFETs with polycrystalline Si1-x-yGexCy gate layers at the gate-oxide interface show substantially reduced boron penetration and increased threshold voltage stability compared to devices with all poly Si gates or with poly Si1-xGex gate layers. Boron accumulates in the poly Si1-x-yGexCy layers in the gate, with less boron entering the gate oxide and substrate. The boron in the poly Si1-x-yGexCy appears to be electrically active, providing similar device performance compared to the poly Si or poly Si1-x-yGex gated devices.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering
- Charge carrier mobility
- Silicon alloys