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In this brief, the hole transport properties of narrow-width germanium-on-insulator (GeOI) pMOSFETs are investigated. We report, for the first time, +65% low-field hole mobility enhancement in narrow-width (0.29-µm effective width Weff) versus large-width (10-µm Weff) GeOI mesa-isolated devices. The observed enhancement, which is independent of the device length down to 90 nm, is attributed to improved sidewall transport properties resulting in higher hole mobility on the sides than on the top of the devices. At high inversion charge density Ninv ~ 1013 cm-2, +55% hole effective mobility improvement is preserved. The top and side low-field mobilities (µtop and µside, respectively) were extracted, showing +90% mobility improvement at the sides (µtop = 125 cm²/V ⋅ s-1 and µside; = 240 cm²/V ⋅ s-1). [ABSTRACT FROM AUTHOR]

We present in this letter the most aggressive dimensions reported to date in Ge-channel transistors: pMOSFETs with 30-nm gate length on ultrathin germaniumon-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 drain OFF-state leakage for Ge-channel devices (< 1 nA/μm at VDS = -1 V) and thus, to the best ON-state to OFF-state current ratio (ION/IOFF ~ 5 × 105), even at Lg = 55 nm. [ABSTRACT FROM AUTHOR]