Donald L. Watrous

MCT (MOS controlled thyristor) reliability investigation

The authors outline some of the ruggedness features observed in recent MCTs. The MCT capabilities described cover the last stages of tests performed on devices that were production-line fabricated and aimed at 400 to 1600 V blocking levels but small enough in die size to be packaged in a TO-220 or TO-218 plastic package. The goal of 100-A operation, a 1-V forward drop at 20 A, and a 1- mu s turn-off time has been achieved in 0.2 to 0.4 cm/sup 2/ production-line-fabricated MCTs. The high-current ruggedness, including di/dt, is due to low forward drop plus uniform MOS-gated turn-on. Turn-off current ruggedness is the result of small cell size and the fact that the MCT blocking junction is flat. High-temperature capability along with excellent noise capability and virtually zero Miller gate capacitance are due to the very dense off-FET shorts and the low (<1 V) FET source-drain voltage and off-FET average current.<<ETX>>