The properties of both lattice-matched and strained doped-channel field-effect transistors (DCFET's) have been investigated in AlGaAs/InxGa1-xAs (0 less than or equal to x less than or equal to 0.25) heterostructures with various indium mole fractions, Through electrical characterization of grown layers in conjunction with the de and microwave device characteristics, we observed that the introduction of a 150-Angstrom thick strained In0.15Ga0.85As channel can enhance device performance, compared to the lattice-matched one, However, a degradation of device performance was observed for larger indium mole fractions, up to x = 0.25, which is associated with strain relaxation in this highly strained channel, DCFET's also preserved a more reliable performance after biased-stress testings.
