InGaAs HEMT with InAs-rich InAlAs barrier spacer for reduced source resistance

An InAlAs/InGaAs HEMT with an InAs-rich barrier spacer (In(0.52)Al(0.48)As) to reduce the parasitic resistance is reported. Devices were obtained with a source resistance of 170 Omega-mu m. A 40 nm gate length In(0.7)Ga(0.3)As HEMT with L(side) = 100 nm and t(ins) = 10 nm shows excellent transconductance and subthreshold characteristics including gm 1.6 mS/mu m, DIBL = 122 mV/V and S = 80 mV/dec at V(DS) = 0.5 V. In addition, this device exhibits an f(T) = 530 GHz and f(max) = 445 GHz at V(DS) = 0.7 V. These excellent characteristics mainly arise from a reduction in the source resistance through the use of the InAs-rich InAlAs spacer.