Novel Fast-switching LIGBT with Single-Step Low-k Dielectric Layer and Assistant-Depletion Trench

A novel low-loss and good-robustness silicon-on-insulator lateral insulated gate bipolar transistor (LIGBT) is proposed and investigated by simulation for the first time. The device is characterized by a single-step low-k dielectric (SSLK) buried layer and assistant depletion trench (ADT) which is shorted with cathode electrode. By the method of electric field modulation, the introduction of the SSLK structure makes electric field distribution more uniform to greatly improve the breakdown voltage performance, which is beneficial for the proposed LIGBT to acquire a drift region of shorter size and a smaller number of stored carriers. From TCAD simulation, the breakdown voltage of the proposed SSLK LIGBT is increased by 61.6% compared with conventional (Conv.) LIGBT under the same length of drift region. Furthermore, while maintaining the same forward voltage drop of 1.17 V, the turn-off energy of the proposed SSLK LIGBT is reduced by 86.4% compared with Conv. LIGBT. Besides, as a result of the ADT structure, the short-circuit failure time of the proposed device is 31.7% longer than that of Conv. LIGBT. Therefore, the proposed SSLK LIGBT shows not only a better trade-off between turn-off loss and forward voltage drop but also an improved short-circuit robustness.

Automated summary

A novel low-loss and good-robustness silicon-on-insulator lateral insulated gate bipolar transistor (LIGBT) with a single-step low-k dielectric (SSLK) buried layer and assistant depletion trench (ADT) is proposed and investigated. The device shows improved breakdown voltage performance, reduced turn-off energy, and increased short-circuit robustness compared to conventional LIGBT.