Inversion-Type Enhancement-Mode InP Mosfets with ALD High-K Al2O3 and HFO2 as Gate Dielectrics

Enhancement-mode (E-mode) n-channel InP metal-oxide-semiconductor field-effect-transistors (MOSFETs) with 0.75 to 40 mum gate length fabricated on semi-insulating substrates and p-type doped InP epi-layers with atomic-layer-deposited (ALD) Al
₂
O
₃
and HfO
₂
as gate dielectrics are demonstrated. The ALD process on III-V compound semiconductors enables the formation of high- quality gate oxides and unpinning of Fermi-level on compound semiconductors. A 1-mum gate-length E-mode n- channel MOSFET with a HfO
₂
gate oxide thickness of 10 nm shows a maximum drain current of 130 mA/mm and a trans- conductance of 40 mS/mm at the highest gate bias of 6 V.