High threshold uniformity, millimeter-wave p/sup +/-GaInAs/n-AlInAs/GaInAs JHEMTs

High threshold voltage uniformity p/sup +/-GaInAs/n-AlInAs/GaInAs millimeter-wave junction-modulated HEMT's are reported. Devices with 0.2 μm gatelength exhibit a standard deviation in threshold voltage of 13.7 mV across a 1×1.5 in
²
wafer. The uniformity is achieved in devices which exhibit high DC transconductance (520 mS/mm), high unity-gain cut-off frequencies: f
_T
(105 GHz) and f
_max
(exceeding 200 GHz), and low minimum noise figure (0.45 dB) with high associated gain (14.5 dB) at 12 GHz.