We report a novel metal–insulator–semiconductor (MIS) structure exhibiting a pseudomorphic In0.05Ga0.95As layer on GaAs with interface state densities in the low 1011eV−1 cm−2. The structure was grown by a combination of molecular beam epitaxy and chemical vapor deposition methods. The hysteresis and frequency dispersion of the MIS capacitor were lower than 100 mV, some of them as low as 30 mV under a field swing of about ±1.3 MV/cm. The 150-Å-thick In0.05Ga0.95As channel between Si and GaAs is found to bring about a change in the minority carrier recombination behavior of the GaAs channel, in the same way as done by In0.53Ga0.47As channel MIS structures. Self-aligned gate depletion mode In0.05Ga0.95As metal–insulator–semiconductor field-effect transistors having 3 &mgr;m gate lengths exhibited field-effect bulk mobility of 1400 cm2/V s and transconductances of about 170 mS/mm. ©1997 American Institute of Physics.