Compound semiconductor MOSFETs

Enhancement mode, high electron mobility MOSFET devices have been fabricated using an oxide high-κ gate dielectric stack developed using molecular beam epitaxy. A template layer of Ga2O3, initially deposited on the surface of the III-V device unpins the GaAs Fermi level while a (GdxGa1−x)2O3 bulk ternary layer forms the highly resistive layer to reduce leakage current through the dielectric stack. A midgap interface state density of ∼2 × 1011 cm−2 eV−1 and a dielectric constant of 20 are determined using electrical measurements.. N-channel MOSFETs with a gate length of 1 μm and a source-drain spacing of 3 μm show a threshold voltage, saturation current and transconductance of 0.11 V, 380 mA/mm and 250 mS/mm, respectively.