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