Measurements of the velocity-field characteristic in AlGaN/GaN heterostructures

Abstract

AlGaN/GaN test structures, with an etched constriction have been fabricated and tested with, and without, a gate. A pulsed voltage input with a 200 ns pulse width and a four-point measurement were used in a 50 Ω environment to determine the room temperature velocity-field characteristic of the structures. A low field mobility of 250 cm 2 /V s and an estimated electron velocity of ∼2×10 7 cm/s was attained at a field of 180 kV/cm.