Studies of buried oxide properties on nanoscale GeOI pMOSFETs for design of a high performance common source amplifier

Using well-calibrated TCAD simulation we explore, for the first time, the impact of buried oxide (BOX) thickness and dielectric constant on the analog circuit performance of 30-nm ultra-thin body germanium-on-insulator (GeOI) pMOSFETs. Our findings show that GeOI MOSFETs with a 20 nm SiO2 BOX offer lower subthreshold leakage current, high transconductance, improved transconductance generation factor and high intrinsic voltage gain. Furthermore, while GeOI MOSFETs with a 20 nm thin HfO2 BOX exhibit the lowest output conductance and highest voltage gain, GeOI MOSFETs with a 200 nm thick HfO2 BOX yield the highest transconductance and unity gain cut-off frequency. Moreover, we design common source amplifiers using GeOI pMOSFETs, analyze and optimize their performance. Our results show that the highest amplifier gain of 6.18 and gain bandwidth of 15.32 GHz are obtained with 20 nm HfO2 BOX while the highest bandwidth of 3.85 GHz is achieved at BOX thickness of 200 nm.