Thermal Cycling Reliability of Polycrystalline Diamond and Aluminium Nitride Substrates

In this paper, thermal cycling of silicon power semiconductor dies mounted on polycrystalline diamond and aluminum nitride insulated substrates is presented. Thermal strain, stress and safety factor was analysed using ANSYS (R) static structural analyses tool to understand the dependence of thermal strain and stress. Polycrystalline diamond system exhibits higher thermal stress and low safety factor when compared over aluminium nitride system, further the thermal stress and safety factor were analysed based upon varying insulation layer thicknesses. Simulation results predict that thermal stress is inversely proportional to insulation layer thickness and proportionally to metallisation thickness.