Statistical Analysis of the Impact of Anode Recess on the Electrical Characteristics of AlGaN/GaN Schottky Diodes With Gated Edge Termination

Abstract

In this paper, we have extensively investigated the impact of anode recess on the reverse leakage current, forward voltage ( ${V}_{F}$ ), and dynamic characteristics of Au-free AlGaN/GaN Schottky barrier diodes with a gated edge termination (GET-SBDs) on 200-mm silicon substrates. By increasing the number of atomic layer etching (ALE) cycles for anode recessing, we have found that: 1) the reverse leakage current is strongly suppressed due to a better electrostatic control for pinching off the channel in the GET region; a median leakage current of $\sim 1$ nA/mm and an ${I}_{\mathrm{\scriptscriptstyle ON}}/{I}_{\mathrm{\scriptscriptstyle OFF}}$ ratio higher than $10^{8}$ have been achieved in GET-SBDs with six ALE cycles; 2) the forward voltage ( $\sim 1.3$ V) is almost independent of the ALE cycles, taking into account its statistical distribution across the wafers; 3) when the remaining AlGaN barrier starts to be very thin (in the case of six ALE cycles), a spread of the ON-resistance, mainly attributed to the GET region, can occur due to the difficult control of the remaining AlGaN thickness and surface quality; and 4) the dynamic forward voltage of GET-SBDs shows a mild dependence on the ALE process in pulsed $I$ – $V$ characterization, and a more ALE-dependent dynamic ON-resistance is observed.