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

Abstract

In this letter, we have successfully transferred the 4inch crack-free GaN films from sapphire substrate to conductive silicon wafer by employing eutectic bonding and laser lift-off (LLO) techniques. The resultant 1-mm 2 fully-vertical GaN Schottky barrier diodes (SBDs) exhibit a high current swing of 10 9 , a low ideality factor of 1.03 and a high forward current of 10 A. Meanwhile, a decent breakdown voltage of 312 V is achieved, which is over 3 times higher than that of control device without performing epitaxial lift-off. Most importantly, such rectifiers show significantly enhanced electrothermal ruggedness, achieving a high surge-current density of 2.6 kA/cm 2 and a low thermal resistance of 0.77 Kcm 2 /W. In addition, the excellent power rectification capability with a low reverse recovery time of 14 ns is obtained under high-speed switching condition with a high current ramp rate (di/dt) of 275 A/µs, implying the desired functionality of the LLO-vertical device architecture. These results thus present the great potentials of the substrate-transferred GaN SBDs for high-power and high-efficiency applications.

Fully-vertical GaN-on-SiC Schottky barrier diode with ultrathin AlGaN buffer layer

“…A slightly lower measured BV of 214 V indicates the good crystal quality of the drift layer as well as the effectivity of the edge termination of this work. foreign substrates [10,11,[32][33][34][35][36][37][38]. The R ON,sp of this work is lower than the reported results, also suggesting the good conductivity of the epi-stack.…”

Study of the Leakage Current Transport Mechanisms in Pseudo-Vertical GaN-on-Silicon Schottky Diode Grown by Localized Epitaxy

“…However, challenges such as high production costs, variable quality, small wafer size, and limited availability hinder their widespread adoption. Consequently, there has recently been a heightened focus on fabricating vertical power devices on foreign substrates such as silicon, sapphire and QST TM [9,10]. Silicon substrates, highly favored from a commercial point of view, encounter a significant challenge during GaN growth due to the difference in coefficient thermal expansion between GaN and silicon.…”

Study of Leakage Current Transport Mechanisms in Pseudo-Vertical GaN-on-Silicon Schottky Diode Grown by Localized Epitaxy

“…However, challenges such as high production costs, variable quality, small wafer size and limited availability hinder their widespread adoption. Consequently, there has recently been a heightened focus on fabricating vertical power devices on foreign substrates such as sapphire, QST TM and silicon [9,10]. From a commercial standpoint, silicon substrates are heavily favored.…”