Design guidelines suppressing dynamic punch-through in GaN vertical MOSFETs by considering the Poole–Frenkel effect

Abstract

Due to the large ionization energy of Mg acceptors in GaN, dynamic punch-through will occur in vertical GaN MOSFETs. To avoid this, higher doping and/or a thicker p-body region should be utilized. However, this increases the channel resistance. In this letter, we suggest that the Poole–Frenkel (P–F) effect has significant impact on dynamic punch-through because of the high electric field in the depletion region under a large bias voltage. Systematic TCAD simulations of simplified vertical GaN MOSFET structures were carried out. We show that the device design considering the P–F effect results in a reduction in the increase in channel resistance.