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Naohito YOSHIDA Toshiaki KITANO Yoshitsugu YAMAMOTO Takayuki KATOH Hiroyuki MINAMI Takuo KASHIWA Takuji SONODA Hirozo TAKANO Osamu ISHIHARA
A 0.15 µm T-shaped gate AlInAs/InGaAs high electron mobility transistor (HEMT) with an excellent RF performance has been developed using selective wet gate recess etching. The gate recess is formed by a pH-adjusted citric acid/NH4OH/H2O2 mixture with an etching selectivity of more than 30 for InGaAs over AlInAs. The standard deviation of saturation drain current (Idss) is as small as 3.2 mA for an average Idss of 47 mA on a 3 inch diameter InP wafer. The etching time for recess formation is optimized and an ft of 130 GHz and an MSG of 10 dB at 60 GHz are obtained. The extremely low minimum noise figure (Fmin) of 0.9 dB with an associated gain (Ga) of 7.0 dB has been achieved at 60 GHz for a SiON-passivated device. This noise performance is comparable to the lowest value of Fmin ever reported for an AlInAs/InGaAs HEMT with a passivation film.