Hybrid Valence Bands in Strained-Layer Heterostructures grown on Relaxed SiGe Virtual Substrates

摘要

The use of alternative channel materials such as germanium and strained silicon (ε-Si) [3-5] is increasingly being considered as a method for improving the performance of MOSFETs. While ε-Si grown on relaxed Si_(1-x)Ge_x is drawing closer to widespread commercialization, it is currently believed that almost all of the performance benefit in CMOS implementations will derive from the enhanced mobility of the n-MOSFET . In this paper, we demonstrate that ε-Si p-MOSFETs can be engineered to exhibit mobility enhancements that increase or remain constant as a function of inversion density. We have also designed and fabricated ε-Si / ε-Ge dual-channel p-MOSFETs exhibiting mobility enhancements of 10 times. These p- MOSFETs can be integrated on the same wafers as ε-Si n-MOSFETs, making symmetric-mobility CMOS possible.