Flip-Chip AlGaN/GaN Schottky Barrier Diode Using Buried-Ohmic Anode Structure With Robust Surge Current Ruggedness and Transient Energy Sustaining Capability

Abstract

Robust reliability is essential for electronic devices against inductive transient shocks in power switching applications. In this work, rugged surge current tolerance and transient energy sustaining capability are simultaneously demonstrated in AlGaN/GaN Schottky barrier diodes (SBDs) for the first time, which greatly fills the research gap toward the device reliability requirements for inductive switching applications. Such robustness is attributed to the combined advantages of the uniquely designed buried-ohmic anode structure and efficient thermal management enabled by substrate thinning and flip-chip packaging techniques. The resultant device exhibits a high surge current density of 3.4 kA/cm2 (42 A) and a critical transient dissipating energy density of 1.5 J/cm2 (18.6 mJ). All these values are the highest reported in AlGaN/GaN SBDs. In particular, the superior switching performance with nanosecond reverse recovery time is achieved under a 400-V operating condition with a fast di/dt of 200 A/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{s}$ </tex-math></inline-formula> , implying the desired functionality of the proposed device architecture. This work, thus, makes a significant step in reaching the promise of AlGaN/GaN SBDs for high-reliability and high-power applications.