Characteristics of fully quaternaryIn 0.52 (Al 0.8 Ga 0.2 ) 0.48 As/In 0.53 (Al 0.2 Ga 0.8 ) 0.47 Asheterostructures in doped-channel FETs

A fully quaternary In0.52(Al0.8Ga0.2)0.48As/In0.53(Al0.2Ga0.8)0.47As heterostructure was introduced into doped-channel FETs (fully-Q DCFETs) on InP substrates for the first time. Combining the advantages of high quality quaternary InAlGaAs Schottky and channel layers, the authors were able to enhance device gate-to-drain and channel breakdown voltages, and to eliminate the kink effect. This results in an extremely low output conductance (go = 0.6 mS/mm), and a high DC gain ratio (gm/go ≃ 350).