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(TGe = 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 drainoff-state leakage for Ge-channel devices (<1\ nA/atVDS = -1\ V) and thus, to the beston-state tooff-state current ratio(ION/IOFF ~ 5 × 10⁵), even atLg = 55\ nm.