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 (V-th) 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/mu m at V-DS = -1 V) and thus, to the best ON-state to OFF-state current ratio (I-ON/I-OFF similar to 5 x 10(5)), even at L-g = 55 nm.