Single-crystal Ge nanowires are synthesized by a low-temperature ͑275°C͒ chemical vapor deposition ͑CVD͒ method. Boron doped p-type GeNW field-effect transistors ͑FETs͒ with back-gates and thin SiO 2 ͑10 nm͒ gate insulators are constructed. Hole mobility higher than 600 cm 2 /V s is observed in these devices, suggesting high quality and excellent electrical properties of as-grown Ge wires. In addition, integration of high-HfO 2 ͑12 nm͒ gate dielectric into nanowire FETs with top-gates is accomplished with promising device characteristics obtained. The nanowire synthesis and device fabrication steps are all performed below 400°C, opening a possibility of building three-dimensional electronics with CVD-derived Ge nanowires.

The main challenges for Tunnel FETs are experimentally demonstrating SS<60mV/dec, high ON currents and solving their ambipolar behavior. We have experimentally demonstrated a Double-Gate, Strained-Ge, Heterostructure Tunneling FET (TFET) exhibiting very high drive currents and SS<60mV/dec. Due to small bandgap of s-Ge and the electrostatics of the DG structure, record high drive current of 300uA/um (the highest ever reported experimentally for a TFET) and a subthreshold slope of ~50mV/dec was observed. In addition, to address the ambipolar problem and examine the scalability of TFETs, we have developed a sophisticated TFET simulator that uses a Quantum transport model, Non-local BTBT, complete Bandstructure (real and complex) information, and includes all transitions (direct and phonon assisted). Using this simulator, we have studied the scalability of three asymmetric DG TFET configurations (underlapped drain, lower drain doping and lateral heterostructure) in terms of their ability to solve the ambipolar behavior and achieve high ON and low OFF currents.

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Abstract-Passivation of Ge has been a critical issue for Ge MOS applications in future technology nodes. In this letter, we introduce ozone-oxidation to engineer Ge/insulator interface. Interface states (D it ) values across the bandgap and close to conduction bandedge were extracted using conductance technique at low temperatures. D it dependency on growth conditions was studied. Minimum D it of of 3x10 11 cm -2 V -1 was demonstrated. Physical quality of the interface was investigated through Ge 3d spectra measurements. We found that the interface and D it is strongly affected by the distribution of oxidation states and quality of the suboxide.