Abstract :
The work presents a simple design/technological procedure that leads to a substantial increase of the peak switched anode current density jTCMand of the efficiency of gate control during the turn-off process in gate turn-off (GTO) and gate-assisted turnoff (GAT) thyristors. The high-voltage (≥2 kV) high-current (600 A) GTO/GAT thyristors with an active area of only 1.7 cm2are based upon the novel double-interdigitated (TIL) gate-cathode concept with a simple geometry, which lends the opportunity to obtain a fair balance between cost effectiveness and overall device performance. The manufacturability ease of developed devices is accompanied by a relaxation of the trade-off between the doping/width of the p-base and the main device parameters, which was a crucial issue in conventional GTO´s/ GATT´s. One of the major benefits obtained through the implementation of the TIL concept in high-power GTO´s, capable of safely switching off an anode current density of JTCM> 350/cm2, is the increase of the operational turn-off gainG_{off} beyond the value of 10, which is beneficient from the standpoint of gate drive circuitry. Another foremost result is the achieved high factor (5 to 8) of the tui:n-off time tqreduction in 2-kV TIL GATT´s with a gate-assist of only IGR= 3 to 4 A, which points to the lack of incompatibility at the fundamental level between a wider n-base and a reduced tq. The developed devices possess a virtual immunity to internal noise signals (extremely high dV/dt capability). The gold-doped TIL-type GTO/GAT thyristors exhibited an excellent turn-on sensitivity, low on-state losses, and a good surge current capability.
