Sub-micron, metal gate, high-к dielectric, implant-free, enhancement-mode III-V mosfets

The performance of 300 nm, 500 nm and 1 mum metal gate, implant free, enhancement mode III-V MOSFETs are reported. Devices are realised using a 10 nm MBE grown Ga₂O₃/(Ga_xGd_1-x)₂O₃ high-kappa (kappa=20) dielectric stack grown upon a delta-doped AlGaAs/InGaAs/AlGaAs/GaAs heterostructure. Enhancement mode operation is maintained across the three reported gate lengths with a reduction in threshold voltage from 0.26 V to 0.08 V as the gate dimension is reduced from 1 mum to 300 nm. An increase in transconductance is also observed with reduced gate dimension. Maximum drain current of 420 muA/mum and extrinsic transconductance of 400 muS/mum are obtained from these devices. Gate leakage current of less than 100 pA and subthreshold slope of 90 mV/decade were obtained for all gate lengths. These are believed to be the highest performance sub-micron enhancement mode III-V MOSFETs reported to date.