Exploring the thermal limit of GaN power devices under extreme overload conditions. (September 2017)

• Record Type: Journal Article
• Authors: Pribahsnik, F.P.; Nelhiebel, M.; Mataln, M.; Bernardoni, M.; Prechtl, G.; Altmann, F.; Poppitz, D.; Lindemann, A.
• Is Part Of: Microelectronics and reliability. Volume 76/77(2017)
• Page Start: 304
• Page End: 308
• Publication Date: 2017-09
• Subjects: Electronic apparatus and appliances -- Reliability -- Periodicals; Miniature electronic equipment -- Periodicals; Appareils électroniques -- Fiabilité -- Périodiques; Équipement électronique miniaturisé -- Périodiques; Electronic apparatus and appliances -- Reliability; Miniature electronic equipment; Periodicals; 621.3815
• DOI: 10.1016/j.microrel.2017.07.046
• Languages: English
• ISSNs: 0026-2714

Abstract

Abstract: The performance of normally-off Gallium-Nitride (GaN) High-Electron-Mobility-Transistors (HEMTs) under extended short circuit operation is investigated. A thermal limit is found in the aluminium metallization, where at temperatures around 600 °C a protrusion of the gate metal through the Inter-Level Dielectric (ILD) may form, short-circuiting gate and source metallization and thus resulting in a permanently-off failure state. The present work shows how this particular failure mode can be induced by extreme overload operation, and presents a Finite Element (FE) model which agrees with the experimental observations and gives insights in the mechanical stress-state developing in the device. The deeper thermo-mechanical understanding of the degradation mechanism suggests directions in order to improve the device's robustness. Highlights: Novel failure mode in power GaN devices has been studied Failure mode explained by thermal-transient and thermo-mechanical FEM simulation Failure mode root cause is an overstress located in the interlayer dielectric