First demonstration of threshold voltage control by sub-1V back-gate biasing for thin body and buried-oxide (TBB) Ge-on-insulator (GOI) MOSFETs for low-power operation

摘要

Introducing high-mobility channel materials such as Ge is an effective way to reduce the power supply voltage because its higher current drivability leads to lower gate-overdrive voltage under a given Ion spec. On the other hand, thin body and buried-oxide (BOX) Si-On-Insulator(SOI) MOSFETs have been intensively investigated in terms of better short-channel effects and efficient Vth controllability[1–4]. Combining these technologies might be bring about further reduction in power consumption in LSIs. Although a Ge-on-insulator (GOI) MOSFET with a thick (330nm) BOX layer have been demonstrated, a significantly high back-gate bias, Vbg ∼50V is required to shift Vth only ∼100mV[5]. A thin-body GOI substrate with an acceptable quality and a sufficiently thin BOX layer of ∼10nm had not been realized. In this work, we demonstrate the thin-body and BOX (TBB)-GOI MOSFETs by using a high quality bonded GOI substrate with Al2O3/SiO2 hybrid BOX structure for the first time. Short channel MOSFET operation and efficient Vth tuning by sub-1V back-gate biasing are experimentally demonstrated.