Abstract :
Major aspects of gate-turn-off (GTO) thyristors are discussed, including device modeling, design considerations, basic research on their switching phenomena, electrical characteristics, and applications. A device design is considered which would increase the maximum interruptible anode current IATO and blocking voltage while decreasing the switching time and power dissipation. The most difficult design problem is to determine the dominant factors that affect IATO. From experimental and computational results, it is found that IATO is increased by a reduced p-base sheet resistance, a thicker n-base layer and an increased gate-cathode breakdown voltage. The turn-off performance is also improved by introducing several modified device structures, such as an anode-shorted emitter construction, an asymmetric n+-doped based structure, a buried gate, and a cathode emitter heterojunction GTO thyristor. Typical characteristics are given for a 5000-V 3000-A unit. GTO applications are discussed, including variable-voltage variable-frequency inverter-controlled AC induction motor drive systems and PWM converter systems
Keywords :
semiconductor device models; thyristors; 3000 A; 5 kV; GTO thyristors; PWM converter systems; anode-shorted emitter construction; blocking voltage; buried gate; cathode emitter heterojunction GTO thyristor; device design; device modeling; dominant factors; drive systems; electrical characteristics; gate-cathode breakdown voltage; maximum interruptible anode current; p-base sheet resistance; power dissipation; switching phenomena; switching time; variable-voltage variable-frequency inverter-controlled AC induction motor; Annealing; Anodes; Cathodes; Charge carrier lifetime; Electric variables; Integrated circuit modeling; Power conversion; Power dissipation; Thyristors; Voltage;
