Al0.3Ga0.7As/InxGa1-xAs (0≤x≤0.25) doped-channel field-effect transistors (DCFET´s)

The properties of both lattice-matched and strained doped-channel field-effect transistors (DCFET´s) have been investigated in AlGaAs/In_xGa_1-xAs (0≤x≤0.25) heterostructures with various indium mole fractions. Through electrical characterization of grown layers in conjunction with the dc and microwave device characteristics, we observed that the introduction of a 150-Å thick strained In_0.15Ga_0.85As 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.