Transcript PPT
Modeling, Fabrication and Test Results of a MOS Controlled Thyristor - MCT - with High Controllable Current Density. Evgeny Chernyavskiy1, Vladimir Popov1, Bert Vermeire2 1 Institute 2 of Semiconductor Physics SB, RAS, Lavrentev pr. 13, Novosibirsk, Russia. Ridgetop Group Inc., 6595 N. Oracle Road, Tucson AZ, USA. MCT Multi-cell Structure and Equivalent Circuit: PMOS channel resistance: Emitter cells: 144,000 Emitter cell size: 10 x 10 mm MCT current limitation: Active area: 0.33 cm2 Breakdown Voltage: 2.5 kV 2-D p-i-n Diode Model: The 2D p-i-n diode model with N+ emitter shunted by PMOSFET is physically equivalent to the MCT for realistic current densities. The current density modulation coefficient (M) decreases with increasing current density. On-state current density measurements match the p-i-n diode model simulations when carrier lifetime is 25 ms (squares) and when it is 3.5 ms (dots). Jmcc criterion: n: electron concentration Na: acceptor doping profile in the P base Ja: current density before modulation The electron density in the center of the N emitter with gate voltage Ug = -15 V becomes larger than the accepter doping when Ja = 132 A/cm2 New criterion for evaluation of the maximum controllable current density in an MCT: If the electron concentration is lower than the acceptor concentration (n < Na) at when the negative gate voltage is applied, then current density is controllable. We believe this to be due to charge compensation. The experimental maximum controllable current density with a lifetime of 25 ms is 100 A/cm2 (compared to the simulated value of 132 A/cm2). The MCT was irradiated with 2 MeV electrons. The carrier lifetime is reduced to 3.5 ms. The maximum controllable current density increased to 150 A/cm2. Conclusions: • • A 2D physical equivalent static model of the MCT using p-i-n diode equivalent allows the maximum controllable current density to be determined from the carrier concentrations. An MCT with high controllable current density (150 A/cm2) was manufactured and accurately modeled using the static model.