F/sub max/-enhancement in CBE-grown InAlAs/InGaAs HEMT's using novel self-aligned offset-gate technology

Maximum frequency of oscillation (f/sub max/) to cutoff frequency (f/sub T/) ratios up to 2.7 and good microwave characteristics have been achieved by applying an offset self-aligned gate technology to InAlAs/InGaAs HEMTs (high electron mobility transistors) grown by CBE (chemical beam epitaxy). The microwave G/sub m//G/sub ds/ (output conductance) ratio for the devices was 23.5 using L/sub gd/ (gate to drain length)=0.4 mu m while the corresponding f/sub max/ was 251 GHz. The approach described combines the advantages of self-aligned and offset gate technologies.<
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