A Novel Bidirectional AlGaN/GaN ESD Protection Diode

Despite the superior working properties, GaN-based HEMTs and systems are still confronted with the threat of a transient ESD event, especially for the vulnerable gate structure of the p-GaN or MOS HEMTs. Therefore, there is still an urgent need for a bidirectional ESD protection diode to improve the ESD robustness of a GaN power system. In this study, an AlGaN/GaN ESD protection diode with bidirectional clamp capability was proposed and investigated. Through the combination of two floating gate electrodes and two pF-grade capacitors connected in parallel between anode or cathode electrodes and the adjacent floating gate electrodes (C_GA (C_GC)), the proposed diode could be triggered by a required voltage and possesses a high secondary breakdown current (I_S) in both forward and reverse transient ESD events. Based on the experimental verification, it was found that the bidirectional triggering voltages (V_trig) and I_S of the proposed diode were strongly related to C_GA (C_GC). With C_GA (C_GC) increasing from 5 pF to 25 pF, V_trig and I_S decreased from ~18 V to ~7 V and from ~7 A to ~3 A, respectively. The diode's high performance demonstrated a good reference for the ESD design of a GaN power system.