InAlN/GaN HEMTs With AlGaN Back Barriers

This letter studies the effect of AlGaN back barriers in the dc and RF performance of In_0.17Al_0.83N/GaN high-electron mobility transistors grown on SiC substrates. When compared to conventional structures without a back barrier, the back barrier effectively prevents the degradation of drain-induced barrier lowering and significantly improves the output resistance in sub-100-nm-gate-length devices. The reduction in short-channel effects helps to increase the frequency performance of AlGaN back-barrier devices. For a 65-nm gate length, the current gain cutoff frequency (f_T) of a transistor with an AlGaN back barrier is 210 GHz, which is higher than that of the standard device with the same gate length (f_T = 195 GHz).