Low leakage current in AlGaN/GaN HFETs with preflow of Mg source before growth of u‐GaN buffer layer

Abstract

AbstractAlGaN/GaN heterostructure field‐effect transistors were grown by metalorganic vapor phase epitaxy on Fe‐doped GaN substrates with a preflow of the Mg source. We realized a low drain leakage current, 1.05 µA/mm, at VDS = 20 V and VGS = −5 V with LGD = 3 µm. This leakage current was one order of magnitude lower than that obtained without a preflow of the Mg source. The breakdown voltage was over 250 V with LGD = 10 µm. The on resistance was estimated to be 3.6 mΩ cm2. No significant redistribution or memory effect of Mg was observed by secondary ion mass spectroscopy measurement.