How Can a Cutting-Edge Gallium Nitride High-Electron-Mobility Transistor Encounter Catastrophic Failure Within the Acceptable Temperature Range?

Abstract

Commercial gallium nitride (GaN) high-electronmobility transistors used for power electronics applications show superior performance compared to silicon (Si)-based transistors. Combined with an increased radiation hardening properties, they are key candidates for high-performance power systems in a harsh environment, such as space. However, for this purpose, it is key to know the potential failure mechanisms (FMs) of the devices in depth. Here, we demonstrate how the repeated thermomechanical stress in a power cycling (PC) test within specified operating conditions destroys the GaN device. Based on leakage current localization analysis, we identify an FM with a yet unknown root cause. Utilizing emission microscopy, focused ion beam cutting, and scanning electron microscope techniques, it is revealed that multilayer cracks of a GaN die are triggered by a commercial leading package structure, which shows excellent capability under frequent thermomechanical stress. Through multiphysics simulations, it is shown that the structural factors that lie behind the strong performing component properties inside the package ultimately are directly related to the failure pattern. This article is accompanied by a video demonstrating dynamic thermal distribution difference between thermography measured in a practical experiment and a multiphysics simulation result during a single PC of a PC test. This article is accompanied by a supplementary figures file demonstrating test environment, preparation process of specimens, and reverse engineering results for the simulation model.

Power Electronics Reliability: State of the Art and Outlook

“…This work studies the threshold voltage shift and dynamic on-state resistance change due to the trapping effect. Thermo-mechanical-related power cycling test is performed in [42][43][44][45] with temperature swings of 100°C or above. Drain-to-source off-state leakage current (IDSS) failure is reported in [42,43].…”

“…Drain-to-source off-state leakage current (IDSS) failure is reported in [42,43]. The failure mechanism is identified in [44] by post-failure analysis tools and detailed FEM simulations. This reveals that the thermo-mechanical stresses induced by an acceptable temperature range can cause multilayer cracks in the die of the GaN device.…”

“…The degradation of power electronic components typically occurs at the material or interconnection level, which needs advanced physics analysis tools [44] to identify the location and structure change. Nevertheless, because the changes of materials and interconnections affect the electro-thermal aspect parameters, they can be used as health precursors to indirectly estimate the degradation level.…”

Evaluation of GaN HEMTs in H3TRB Reliability Testing

“…Song et al have evaluated GaN cascode HEMTs under surge current events and transient overvoltage conditions [9]. There have also been works focused on accelerated aging due to thermal stresses from thermal power cycling between 25 and 125 • C [10]. S. Song et al observed electrical cracks in the degraded devices, corresponding to increased leakage current, while the threshold voltage and on-state resistance have been unaffected [11].…”

System-Level Reliability Modeling and Evaluation in Power Electronic-based Power Systems

“…Likewise, [28] investigates the aging mechanisms of Insulated-Gate Bipolar Transistors (IGBTs) -a widely used component in power electronic converters -due to power cycling, where the results have been verified experimentally. In [29], the effect of thermomechanical stresses on the aging mechanisms of a Gallium Nitride transistor -a cutting-edge semiconductor for power electronic application -has been explored.…”