Polyimide passivation approaches on double-mesa thyristors

Polyimide layers have been applied by a simple blade squeeze technique on double-mesa high voltage thyristor devices for its electrical passivation. Reverse and forward electrical blocking characteristics were measured as a function of polyimide application and curing processing conditions. During high temperature reverse bias reliability test, the thyristors showed appreciable leak-current increment, but after three day thermal process, the devices showed lower leakage currents than that devices fabricated by conventional glassivation technique.