High-voltage AlGaN/GaN HEMTs fabricated on free-standing GaN substrates

Abstract

This paper describes DC characteristics of AlGaN/GaN high electron mobility transistors (HEMTs) fabricated on a free-standing GaN substrate. The three terminal breakdown voltage of the fabricated HEMT with a gate length of 3 μm exhibited a linear increase with increasing the gate-to-drain distance (Lgd), reaching more than 1200 V at Lgd=25 μm. It was found that the ON/OFF ratio in the drain current was only 104, indicating the need for further improvements in buffer structure design.