On-Chip Gate ESD Protection for AlGaN/GaN E-Mode Power HEMT Delivering >2kV HBM ESD Capability

In this work, we proposed an on-chip protection circuit to enhance the gate ESD robustness for the AlGaN/GaN E-mode power HEMT, based on the monolithic 8” GaN-on-Si technology platform. The developed circuit features: 1) a voltage divider formed by 2 lateral field-effect-rectifiers and a 2DEG resistor in series; 2) a discharge HEMT with its G/S parallel to the resistor and D/S parallel to the G/S of the power HEMT. In a forward gate ESD event, the discharge HEMT starts to dissipate energy when the voltage drop across the 2DEG resistor is higher than its Vth. While in a reverse gate ESD event, the discharge HEMT operates in the reverse diode connection mode to conduction current. A forward/reverse turn-on of $\sim$ +5V/-2V was experimentally demonstrated without affecting normal gate off/on operation between 0V/5V. TLP tests demonstrated a forward/reverse peak gate current of + 3.2A and <−5.3A, and HBM tests showed forward/reverse G-S ESD capability higher than 2kV.