High temperature die-attach materials for aerospace power electronics: Lifetime tests and modeling

Abstract

Increasing the temperature in power electronic applications usually causes a decreasing lifetime and reliability. This study shows that packaging materials and technologies, such as silver-sintering or gold germanium solders combined with silicon-carbide devices, can easily deal with temperatures above 200 °C/392 °F. Furthermore, lifetime tests (active power cycling) with 300 devices offered more cycles to failure at 120 °C/248 °F heat sink temperature than at 40 °C/104 °F (same ΔT) for silver-sintered samples and goldgermanium solders. SAC305 and tin-lead solders were also tested for comparison but could not withstand the harsh conditions. The samples were silicon carbide diodes attached to copper-ceramic-substrates (DBCs). For testing, the devices were heated up by current to ach ieve a 130 K temperature swing at different coolant temperatures (250 °C/482 °F maximum temperature). The reason behind the higher lifetime at elevated temperatures is the increasing ductility over temperature. The materials capability against thermomechanical stress is better at higher temperatures, while creep effects are not dominating. This effect can be used especially for high temperature application with extraordinary requirements on lifetime and reliability. Analytical models based on stress strain calculations can explain this material behavior. Together with an in-situ measurement of the thermal impedance the models can predict the lifetime consumption of the application and thereby upcoming maintenance

Investigation on the Tribological Behaviors of as-sprayed Al2O3 Coatings With the Effects of MoS2 Lubricant and External Loads

“…With the continuous development and improvement of science and technology, traditional materials in some emerging industries have been far from satisfying the needs of the requirements. Especially in the eld of electronics and aerospace, the materials are required to have the properties of oxidation resistance, high-temperature resistance and wear resistance [1][2][3][4]. Although metal and alloy materials possess good toughness, machinability and conductivity, their wear resistance, corrosion resistance and high-temperature resistance are poor [5][6][7].…”