Modulation of the high mobility two-dimensional electrons in Si/SiGe using atomic-layer-deposited gate dielectric -: art. no. 142103

Metal-oxide-semiconductor field-effect-transistors using atomic-layer-deposited (ALD) Al2O3 as the gate dielectric are fabricated on the Si/Si1-xGex heterostructures. The low-temperature carrier density of a two-dimensional electron system (2DES) in the strained Si quantum well can be controllably tuned from 2.5x10(11) to 4.5x10(11) cm(-2), virtually without any gate leakage current. Magnetotransport data show the homogeneous depletion of 2DES under gate biases. The characteristic of vertical modulation using ALD dielectric is shown to be better than that using Schottky barrier or the SiO2 dielectric formed by plasma-enhanced chemical-vapor-deposition. (C) 2005 American Institute of Physics.