The pseudomorphic properties of doped-channel field-effect transistors have been thoroughly investigated based on A]GaAs/InGa1-xAs (0 less-than-or-equal-to x less-than-or-equal-to 0.25) heterostructures with different In contents. Through various analytical schemes and device characterization, we observed that by introducing a 150 angstrom strained In0.15Ga0.85As channel we can enhance device performance; however, this strained channel is not stable after high-temperature heat treatment. By further increasing the In content up to x = 0.25, the device performance started to degrade, which is associated with strain relaxation in this highly strained channel.
