Design of InAlAs/InGaAs PHEMTs and small-signal modeling from 0.5 to 110 GHz

摘要

90-nm T-shaped gate InP-based In_(0.52)Al_(0.48)As/In_(0.6)Ga_(0.4)As pseudomorphic high electron mobility transistors were designed and fabricated with a gate-width of 2 × 30 μm, a source-drain space of 2.5 μm, and a source-gate space of 0.75 μm. DC, RF and small-signal model characterizations were demonstrated. The maximum saturation current density was measured to be 755 mA/mm biased at V_(gs) = 0.6 V and V_(ds) = 1.5 V. The maximum extrinsic transconductance was measured to be 1006 mS/mm biased at V_(gs) = -0:1 V and V_(ds) = 1.5 V. The extrapolated current gain cutoff frequency and maximum oscillation frequency based on S-parameters measured from 0.5 to 110 GHz were 180 and 264 GHz, respectively. The inflection point (the stability factor k = 1) where the slope from -10 dB/decade (MSG) to -20 dB/decade (MAG) was measured to be 83 GHz. The smallsignal model of this device was also established, and the S-parameters of the model are consistent with those measured from 0.5-110 GHz.