Test Bench for Static, Dynamic and Thermal Cycling Tests of Power Semiconductor Transistors at Cryogenic Temperatures

Cryogenic electronics remains a promising direction for increasing the power density of power converters. However, the reliability characteristics of power semiconductor components cooled by cryogenic liquids remain insufficiently studied. At the same time, the reliability forecast is crucial for increasing the technological readiness of solutions based on power cryoelectronics. The article describes the modernization of a thermal cycling test bench for power diodes into a comprehensive test platform for power transistors. The main changes include the modernization of the nitrogen supply system and the electrical circuit to provide semi-automated thermal cycling, double-pulse and static tests. During the debugging stage of the test bench, several power transistors were tested, including Russian-made gallium nitride high electron mobility transistors (GaN HEMTs). A significant decrease in static losses at cryogenic temperatures was noted for the tested transistors, and the dynamic processes underwent only minor changes. As a result of the work done, the test bench not only supports individual test types, but also allows alternating test types within a single program. This capability allows the effects of cryogenic thermal cycling to be investigated on both the static and dynamic characteristics of transistors. Notably, the electrical subsystem of the test bench can also be used independently for room temperature testing.