Metal-oxide-semiconductor field-effect-transistors using atomic-layer-deposited (ALD) Al2 O3 as the gate dielectric are fabricated on the Si Si1-x Gex heterostructures. The low-temperature carrier density of a two-dimensional electron system (2DES) in the strained Si quantum well can be controllably tuned from 2.5× 1011 to 4.5× 1011 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 Si O2 dielectric formed by plasma-enhanced chemical-vapor-deposition.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)