Extending Si CMOS: InGaAs and GeSn High Mobility Channel Transistors for Future High Speed and Low Power Applications

Abstract

Introduction of high mobility channels is a promising way for high-speed and low-power logic applications beyond 11-nm technology node. InGaAs and GeSn have become of great interest owing to their high electron and hole mobilities, respectively. This thesis aims to address various challenges to take full advantage of the high mobility channel materials for future CMOS logic applications. For In0.7Ga0.3As N-MOSFETs, an in-situ SiH4 doping during the selective epitaxy of raised S/D regions was developed to reduce transistor S/D resistance. Two advanced technology schemes: InP capping and low-temperature Si2H6 passivation, were then explored to realize high-quality gate stack for In0.7Ga0.3As N-MOSFETs. For GeSn P-MOSFETs, low temperature Si2H6 passivation was first developed to realize high-quality high-k/GeSn interface and excellent transistor reliability. The drive current of GeSn P-MOSFETs was further enhanced by optimization of surface orientations and channel length scaling. The first uniaxially strained GeSn GAA nanowire P-MOSFET was finally demonstrated.