The linearities of pseudomorphic heterostructure Al0.3Ga0.7As/In0.2Ga0.8As doped-channel FET's (DCFET's) and HEMT's were evaluated by DC and RF testings. Due to the absence of parallel conduction in the doped-channel approach, as compared to the modulation-doped structure, a wide and flat device performance together with a high current density was achieved. This improvement of device linearity suggests that doped-channel designs are suitable for high frequency power device application.
