Analysis of lateral surface leakage in the vicinity of Schottky gates in AlGaN/GaN HEMTs

摘要

Schottky gates on AlGaN/GaN HEMTs are reducing their size to nanometer-scale region for the demand of further high-frequency operation. In those devices, the gate leakage includes not only one dimensional transport, normal to the Schottky interface, but also lateral electron injection from the gate edge. In the latter case, we have to pay attention to the laterally injected charges to the surface states because they can cause the instability of device operation. However, the mechanism of lateral leakage current in the vicinity of Schottky gates is not understood yet for the AlGaN/GaN HEMTs. In this paper, we systematically characterize surface leakage current in the vicinity of Schottky gates on the AlGaN/GaN heterostructure, separating it from the normal leakage current through the Schottky interface.