Development of an Electrostatic Discharge Protection Solution in GaN Technology

In this letter, a robust and effective gallium nitride (GaN)-pHEMT-based electrostatic discharge (ESD) protection structure is developed for the first time. The structure consists of a depletion-mode GaN pHEMT, a trigger diode chain, a pinchoff diode chain, and a current limiter. Results pertinent to critical ESD parameters, such as the trigger voltage, leakage current, on-state resistance, and robustness, are measured using the transmission line pulsing (TLP) tester. It is demonstrated that such an ESD clamp can sustain a TLP stress of up to 3 A. The two diode chains are found to play critical roles in determining the trigger voltage and leakage current. Increasing the trigger diode number increases the trigger voltage. On the other hand, adding more pinchoff diodes also increases the trigger voltage and simultaneously reduces the leakage current. The design tradeoffs for the proposed ESD clamp are also discussed.