Cryogenic Performance of Low-Noise InP HEMTs: A Monte Carlo Study

In this paper, we present a study of the cryogenic performance of InP high electron mobility transistors (HEMTs) in the low-noise region by means of Monte Carlo simulations. A decrease of the contact resistances and an increase in the electron velocity in the channel together with enhanced channel electron confinement upon cooling of the device are observed, and considered to be the reason for the excellent low-noise behavior of cryogenic InP HEMTs. These findings are supported by a good agreement between simulated and experimental DC, RF, and noise figure data of a 130-nm gate length InP HEMT at 300 and 77 K. An increase of the transconductance $g_{m}$ and gate-to-source capacitance $C_{\rm gs}$ is observed when cooling from 300 to 77 K as a consequence of electron velocity increase and improved channel confinement.