Edge termination is one of the key technologies for fabricating high voltage Schottky barrier diodes (SBDs),which could effectively reduce the peak electric field along the Schottky contact edge and enhance the breakdown voltage.We adopt a high-resistivity ring structure as the edge termination for planar GaN SBDs.The edge termination is formed by self-aligned boron implantation on the edge of devices to form a highly damaged layer.In the implant dose and energy ranges studied experimentally,the GaN SBDs show improved blocking characteristics in terms of reverse leakage current and breakdown voltage at higher implant dose or implant energy.Meanwhile,the forward tu-on characteristics of the GaN SBDs exhibit no apparent change.