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

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 similar to 1 nA/mmand an I-ON/I-OFF ratio higher than 108 have been achieved in GET-SBDs with six ALE cycles; 2) the forward voltage (similar to 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.