Extremely High g{sub}m>2.2S/mm and f{sub}T>550GHz in 30-nm Enhancement-Mode InP-HEMTs with Pt/Mo/Ti/Pt/Au Buried Gate

摘要

We have successfully developed 30-nm enhancement-mode (E-mode) InGaAs/InAlAs high electron mobility transistors (HEMTs) with an extremely high transconductance (g{sub}m) of 2.22S/mm, a current gain cutoff frequency (f{sub}T) of 554GHz, and a maximum oscillation frequency (f{sub}(max) of 358GHz. The excellent high-speed performance was obtained by using a Pt/Mo/Ti/Pt/Au buried gate technology, which enabled E-mode operation for very short 30-nm HEMTs while maintaining a low access resistance as well as a low gate leakage current. The effectively short gate-to-channel distance suppressed the short channel effect, resulting in a very high g{sub}m independent of the gate length (L{sub}g) and a greatly reduced output conductance (g{sub}d).