Investigation of Current Collapse Mechanism on AlGaN/GaN Power Diodes

In this paper, a methodology is proposed for studying the current collapse effects of Gallium Nitride (GaN) power diodes and the consequences on the dynamic on-resistance (RON). Indeed, the growing interest of GaN based, high frequency power conversion requires an accurate characterization and a deep understanding of the device's behaviour before any development of power converters. This study can ultimately be used to model observed trap effects and, thus, improve the equivalent electrical model. Using an in-house circuit and a specific experimental setup, a current-collapse phenomenon inherent to gallium nitride semiconductor is studied on planar 650 V-6 A GaN diodes by applying high voltage stresses over a wide range of temperatures. With this method, useful data on activation energy and capture cross section of electrical defects linked to dynamic RON are extracted. Finally, the origins of such defects are discussed and attributed to carbon-related defects.