DC and RF characteristics of In 0.52 Al 0.48 As/In 0.7 Ga 0.3 As HEMTs at 300 and 16 K

Pseudomorphic In 0.52 Al 0.48 As/In 0.7 Ga 0.3 As HEMTs have been fabricated in the gate length L g range of 50 to 700 nm and their DC and RF characteristics measured at 300 and 16 K. The maximum drain‐source current I ds , the maximum transconductance g m_max and the cutoff frequency f T values increased at 16 K as expected. The ratios g m_max (16 K)/ g m_max (300 K) and f T (16 K)/ f T (300 K) decreased with decreasing L g , which results from the enhancement of the ballistic transport of electrons.