Gallium Nitride (GaN) monolithic bidirectional switches (MBDS) are an emerging technology with strong potential to revolutionize AC power conversion. However, the inherently low threshold voltage and narrow gate-voltage headroom of Schottky-type p-GaN devices make gate reliability a critical concern, which remains largely unexplored in GaN-on-Si bidirectional HEMTs. In this work, we report a previously unobserved gate-to-gate crosstalk phenomenon in GaN MBDS. Detailed analysis shows that the effect originates from displacement current coupling through the inter-gate capacitance (CGG), which induces a voltage overshoot and a deep valley on the inactive gate during the active gate’s turn-on and turn-off transients, respectively. Such behavior directly mirrors the switching dynamics of the active gate, raising significant reliability concerns for the inactive gate. These findings highlight that GaN MBDS face more stringent gate reliability challenges than their unidirectional counterparts, suggesting the importance of improved gate structures and driver strategies in future device designs.
