High-speed InP-HEMTs: Low-noise performance and cryogenic operation

We fabricated decananometer-gate InP-based InAlAs/InGaAs high electron mobility transistors (HEMTs) and measured their DC, RF and noise characteristics. We achieved a minimum noise figure NF_min of 1.0 dB at a frequency of 90 GHz, a cutoff frequency f_T of 520 GHz and a maximum oscillation frequency f_max of 425 GHz for a 35-nm-gate pseudomorphic HEMT (P-HEMT) under the same bias condition. We also performed DC and RF measurements and Monte Carlo (MC) simulations of P-HEMTs at 300 and 16 K. We confirmed the improvements of DC and RF performance by cooling. The improvements mainly results from the suppression of the intervalley phonon scattering from the Γ valley to the L valley in InGaAs channel layer. Furthermore, we showed the possibility of low-voltage, low-power and high-speed operations of ultra-short-gate P-HEMTs.