(Invited) MOS Interface Control of High Mobility Channel Materials for Realizing Ultrathin EOT Gate Stacks

One of the most critical issues for Ge/III-V MOSFETs is gate insulator formation. In this paper, we focus on viable Ge/III-V MOS gate stack technologies realizing the requirements of MOS interface quality and thin equivalent oxide thickness (EOT). these requirements. As for Ge gate stacks, we present a ultrathin EOT Al2O3/GeOx/Ge gate stack fabricated by a plasma post oxidation method and pMOSFETs using this gate stack. (100) Ge pMOSFETs using GeOx/Ge MOS interfaces is demonstrated with EOT down to 0.98 nm and high hole peak mobility of 401 cm2/Vs. As for InGaAs gate stacks, we show the impact of Al2O3 inter-layers on interface properties of HfO2/InGaAs MOS interfaces. The 1-nm-thick capacitance equivalent thickness (CET) in the HfO2/Al2O3/InGaAs MOS capacitors is realized with good interface properties and low gate leakage of 2.4e-2 A/cm2.