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.