Sub-micron, Metal Gate, High-к Dielectric, Implant-free, Enhancement-mode III-V MOSFETs

The performance of 300nm, 500nm and 1μm metal gate, implant free, enhancement mode III-V MOSFETs are reported. Devices are realised using a 10nm MBE grown Ga2O3/(GaxGd1-x)2O3 high-κ (κ=20) dielectric stack grown upon a δ-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 μm to 300 nm. An increase in transconductance is also observed with reduced gate dimension. Maximum drain current of 420 μA/μm and extrinsic transconductance of 400 µS/µm are obtained from these devices. Gate leakage current of less than 100pA and subthreshold slope of 90 mV/decade were obtained for all gate lengths. These are believed to be the highest performance submicron enhancement mode III-V MOSFETs reported to date