We demonstrated silicon MOSFET's with a counterdoped ultrathin epitaxial channel grown by low-temperature UHV-CVD; this allows the channel region to be doped with boron with high precision. The boron concentration and epitaxial layer thickness can be chosen independently, and so it is easy to adjust the threshold voltage of the buried-channel p-MOSFET's with ntype polysilicon gates. It was confirmed that choosing an ultrathin epitaxial layer at 10 nm leads to suppression of the short-channel effects in buried-channel p-MOSFET's with gate length down to 0.15 μm, while maintaining an appropriate value of threshold voltage.
- Boron-doped epitaxial Si
- Buried channel type