DOUBLE MODULATION-DOPED STRAINED-CHANNEL ALINAS-GAINAS-ALINAS HEMT STRUCTURES OPERATING AT HIGH DRAIN CURRENT DENSITIES AND MILLIMETER-WAVE FREQUENCIES

Double modulation-doped Al0.48In0.52As/Ga0.35In0.65As HEMTs are shown to yield unprecedented drain current modulation characteristics associated with high maximum unilateral power and current gain cut-off frequencies f(max) and f(T). Fabricated 0.2 mu m-gate-length HEMTs yield maximum f/(max)/f(T) values of 290 / 112 GHz at 800-900 mA/mm, and 160 / 80 GHz at 1350 mA/mm. The high 2DEG density and high saturation current of the channel access regions as well as a low output conductance of the channel are the main features of the presented heterostructure.