Design Guidelines and Performance Tradeoffs in Recessed AlGaN/GaN Schottky Barrier Diodes

Abstract

Critical design parameters for AlGaN/GaN Schottky barrier diodes (SBDs) are analyzed in this work using TCAD computations and detailed experiments. A comprehensive TCAD-based computational modeling approach is developed for GaN-based SBD. Breakdown mechanisms in SBD for unintentionally doped (UID) buffer, Fe-doped buffer and C-doped buffer are studied. For the first time, we have reported impact of anode recess, on breakdown and leakage behavior of SBD, in correlation with interface defects. Using these insights an optimum recess design strategy has been presented and is validated experimentally. Furthermore, for the first time, we have revealed critical repercussions of the field plate termination on SBD's breakdown, leakage as well as transient behavior. Forward and reverse recovery measurements were carried out to study the diode's transient performance as a function of field plate design. Various performance matrices such as diode current collapse, reverse current overshoot and reverse recovery time were studied experimentally as a function of field plate design. Moreover, the field plate-dependent electro-thermal behavior of SBD was studied using TCAD computations and experiments. Using the systematic device design approach we have experimentally demonstrated large periphery SBD with 15 A forward current at 5.5 V.