GeOI pMOSFETs Scaled Down to 30-nm Gate Length With Record Off-State Current

We present in this letter the most aggressive dimensions reported to date in Ge-channel transistors: pMOSFETs with 30-nm gate length on ultrathin germanium-on-insulator substrates (T_Ge = 25 nm). By improving both the Ge-enrichment technique and the transistor fabrication process, we demonstrate devices with controlled threshold voltage (Vth) and excellent short-channel effects. Moreover, the low defectivity and the very low thickness of the Ge film lead to a record drain OFF-state leakage for Ge-channel devices (< 1 nA/??m at V_DS = -1 V) and thus, to the best ON-state to OFF-state current ratio (I_ON/I_OFF ~5 ?? 10⁵), even at Lg = 55 nm.