Special 1400 volt N-MCT designed for surge applications

The MOS controlled thyristor (MCT) is a power switching device which makes use of MOSFET technology to control both the turn-on and turn-off of the thyristor element. The device may be fabricated as either a P-MCT or an N-MCT by switching the dopant polarities of the starting materials and subsequent diffusions (the label is determined by the dopant type of the lower base in the thyristor). The MCT has just entered the commercial marketplace as a P-MCT gender device for general switch applications. The N-MCT, though not as far along in the development cycle, has certain strengths which may be capitalized particularly in applications requiring a turn on switch for large peak currents and dI/dt. The authors review the N-MCT properties which make it suitable for such an application, and discuss the development of a small 1400 volt N-MCT (6.4×6.4 mm die size) which has been applied in a DC breaker circuit where it is used to interrupt as much as 1000 A of fault current