Demonstration of Vertical GaN Schottky Barrier Diode With Robust Electrothermal Ruggedness and Fast Switching Capability by Eutectic Bonding and Laser Lift-Off Techniques

In this letter, we have successfully transferred the 4-inch crack-free GaN films from sapphire substrate to conductive silicon wafer by employing eutectic bonding and laser lift-off (LLO) techniques. The resultant 1-mm2 fully-vertical Schottky barrier diodes (SBDs) exhibit a high current swing of 109, low ideality factor 1.03 forward 10 A. Meanwhile, decent breakdown voltage 312 V is achieved, which over 3 times higher than that control device without performing epitaxial lift-off. Most importantly, such rectifiers show significantly enhanced electrothermal ruggedness, achieving surge-current density 2.6 kA/cm2 thermal resistance 0.77 K.cm2/W. addition, excellent power rectification capability with reverse recovery time 14 ns obtained under high-speed switching condition ramp rate (di/dt) 275 A/?s, implying desired functionality LLO-vertical architecture. These results thus present great potentials substrate-transferred SBDs for high-power high-efficiency applications.