Aluminium corrosion in power semiconductor devices. (October 2022)

• Record Type: Journal Article
• Authors: Leppänen, J.; Ingman, J.; Peters, J.-H.; Hanf, M.; Ross, R.; Koopmans, G.; Jormanainen, J.; Forsström, A.; Ross, G.; Kaminski, N.; Vuorinen, V.
• Is Part Of: Microelectronics and reliability. Volume 137(2022)
• Publication Date: 2022-10
• Subjects: IGBT -- HV-H3TRB -- PoF -- EoL -- ECM -- FIB -- LiT -- MIP -- Aluminium corrosion -- Pourbaix diagram; 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.2022.114766
• Languages: English
• ISSNs: 0026-2714

Abstract

Abstract: In this study, insulated gate bipolar transistor (IGBT) power modules were exposed to high voltage, high humidity, high temperature and reverse bias (HV-H 3 TRB) conditions until end-of-life (EoL). The limited lifetime of power semiconductor devices when used in demanding applications involving high relative humidity during operation is commonly reported to be associated with the design of the edge termination in power transistor or diode chips. A physics-of-failure (PoF) oriented methodology was adopted in failure analysis, including using lock-in thermography (LiT) for failure localisation and using an advanced microwave-induced plasma (MIP) decapsulation technique for the selective etching of the edge termination polyimide passivation film. A focused ion beam (FIB) was utilised to create a cross-section of the samples for both scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) analysis. The evidence gathered using the physics-of-failure methodology were compared with the results from advanced statistical analysis of the failure distributions in Weibull plots, including comparison of α and β parameters. This analysis revealed correlation with the Weibull distributions and the results from the physics-of-failure. Aluminium corrosion products were systematically observed on guard rings (GR) and field plates (FP) showing that the migration of these corrosion products forming an electrical path between the guard rings that seems to be a major failure mechanism in high humidity environments when reverse bias voltage is applied. Highlights: Humidity temperature voltage bias induced failures analysed in power semiconductors. Al corrosion is the dominant failure mechanism in > 1200 V power semiconductors. Al guard ring based the edge termination structures should be carefully dimensioned.