Temperature-Dependent Small-Signal and Noise Parameter Measurements and Modeling on InP HEMTs

In this paper, we present detailed on-wafer S-parameter and noise parameter measurements and modeling of InP/InAlAs/InGaAs high electron mobility transistors (0.1-[micro]m gate length) at cryogenic temperatures. Various physical effects influencing small-signal parameters, especially the radio-frequency (RF) transconductance and RF output resistance and their temperature dependence, are discussed in detail. Accurate on-wafer noise parameter measurements are carried out from 300 to 18 K, and the variation of the equivalent noise temperatures of drain and source ([T.sub.d] and [T.sub.g]) are modeled against temperature. Based on these models, a cryogenic low-noise amplifier in the Ka-band is developed with a record-low noise temperature of 10 K. Index Terms--Cryogenic, high electron mobility transistor (HEMT), impact ionization, low-noise amplifier (LNA), noise, small-signal model.