Improving the transconductance flatness of InAlN/GaN HEMT by modulating VT along the gate width

A modulated V-T HEMT with improved g(m) flatness is demonstrated for high linearity application. The modulated V-T HEMT was achieved by connecting two elements with different V-T values in parallel along the gate width, realizing a flat resulting transfer curve, and the two different V-T elements were fabricated by recessing part area of the barrier along the gate width under the gate region. The proposed HEMT shows a gate voltage swing as high as 5.4 V, a high drain current of approximately 2 A mm(-1), and an f(T)/f(max) of 63/125 GHz with a much flatter profile within the large gate voltage range. (C) 2019 The Japan Society of Applied Physics