Analysis of reverse leakage mechanism in recess-free thin-barrier AlGaN/GaN Schottky barrier diode

Abstract

Abstract In this letter, the reverse leakage mechanism of thin-barrier AlGaN/GaN Schottky barrier diode (SBD) with recess-free technology is reported for the first time. Two types of SBD were fabricated with different AlGaN barrier thickness (5 and 7 nm). It is found that trap-assisted tunneling is the dominant mechanism for area-related leakage current in the Schottky region at low reverse bias, which attributed to the traps introduced by fluorine-based dry etch during opening the LPCVD SiN x cap. When it is highly reverse biased, Schottky edge leakage current becomes dominant for 7 nm SBD, but not for the 5 nm SBD. The suppression of edge leakage in the 5 nm SBD is due to the reduction of the Schottky edge electric field caused by the thinning of the barrier, which was verified by simulation. These findings will help to further optimize the performance of AlGaN/GaN SBD.