High-Voltage (>1.2 kV) AlGaN/GaN Monolithic Bidirectional HEMTs With Low On-Resistance (2.54 mΩ ⋅ cm²)

High-voltage (> 1.2 kV) bidirectional AlGaN/ GaN HEMTs were fabricated with low ON-resistance of $\sim {10} \Omega \cdot \text { mm}$ or specific ON-resistance of 2.54 $\text{m}\Omega \cdot \text { cm}^{{2}}$ . Two field plates with variable lengths were utilized on each side to experimentally optimize the breakdown voltage and notice the trend of breakdown voltage variation with field plate dimensions. It was observed that the total length of the field plates should be kept smaller than a “critical value” to achieve high blocking voltage. The underlying physics of this behavior was explained and justified with TCAD simulations. The highest breakdown voltage in our fabricated devices was 1360 V. A qualitative design guide was proposed for maximizing the breakdown voltage in monolithic bidirectional HEMTs with multiple field plates.