Microwave-Frequency InAlP-oxide/GaAs MOSFETs

GaAs-channel MOSFETs employing InAlP native oxide gate dielectrics and achieving record microwave performance are reported. Devices with 1 mum gate length demonstrate measured f
_t
's of 17.0 GHz with f
_max
's of 74.8 GHz. Improved RF performance is obtained by vertical scaling of the device heterostructure to incorporate a 7.5 nm thick gate oxide layer. Despite the thin InAlP native oxide gate dielectric layer, a low gate leakage current density of 1.58 times 10
^-4
A/cm
²
is obtained at 1 V bias