Improving the Reliability of Silicon Diodes Via Manufacturing Process Modification Strategies

The multicomponent nature of power electronic devices can be an issue for their reliability due to the high currents and temperatures reached during operation. Proper design of each component and the system as a whole is mandatory to ensure a long lifetime and small failure rates. In this work, we systematically investigate the influence of manufacturing on the behavior of press-fit rectifier Si diodes by introducing changes in the manufacturing process. Concretely, we focused on the solder geometry and the epoxy component. Thermography measurements and computational modeling show that optimization of the solder thickness and its uniformity allows the diode to bear higher currents and temperatures close to 250 C in the hottest parts of the device (located in the epoxy zones) without failure. In addition, choosing an adequate epoxy with a limited expansion rate over a wide temperature range helps to reduce stress and strain effects, preventing the breakdown of the diodes even at continuous currents up to 40 A.