Design considerations to enhance the modulation efficiency and cutoff frequency of AlGaN/InGaN/GaN HEMTs

This paper investigates the optimization of design parameters to achieve enhanced modulation efficiency and cutoff frequency in AlGaN/InGaN/GaN HEMTs. The frequency dependent current gain of the device is simulated for different AlGaN thicknesses, taking into account the polarization fields and strain effects. The implementation of an underlap junction is discussed and it is demonstrated that the underlap improves the channel velocity so that current gain cutoff frequency-gate length product of 19.45 GHz-µm can be realized.