可关断SiC基光触发多门极半导体开关仿真研究

Simulation of SiC based turn-off light initiated multi gate semiconductor switches

  • 摘要: 碳化硅(SiC)基光触发多门极半导体开关(LIMS)具有功率容量高,导通速度快的显著优势,在雷达、加速器以及脉冲源等方面广泛应用。针对LIMS存在的下降沿长,关断速度慢等问题,提出了一种具有关断作用的LIMS阳极结构设计。通过实验数据对仿真模型进行校准,并结合仿真对具有关断阳极结构器件的导通特性进行研究。仿真结果表明,具有关断阳极结构的器件,能在激光触发后形成pnpn结构的正反馈效应,增加导通电流。在激光结束后,随着光生载流子的复合,以及关断阳极结构对基区载流子的抽取作用,显著地提高器件的关断速度。当输入电压为4 kV时,在数百A脉冲电流放电条件下,电流脉冲宽度从0.79 μs减小到百ns以下,器件的关断时间降低至0.6 μs,可以在kHz及以上的重复频率场景中应用。

     

    Abstract:
    Background SiC-based light-initiated multi-gate semiconductor switches (LIMS) deliver superior response speeds due to the faster injection of photo-generated carriers compared to conventional electrically injected carriers. They can be used in a variety of applications, including radars, accelerators, and pulse sources.
    Purpose Regarding the problems such as the long falling edge and slow turn-off speed of LIMS, an anode structure design with turn-off capability is proposed.
    Methods The model and its parameters are calibrated based on experimental data, and the simulation is used to study the conduction characteristics of devices with a turn-off anode structure.
    Results The simulation results show that devices with a turn-off anode structure can achieve positive feedback in the pnpn configuration following laser activation, thereby increasing the conduction current. When the laser pulse ends, the recombination of photo-generated carriers and the extraction of carriers from the base region by the turn-off anode structure significantly enhance the turn-off speed of the device.
    Conclusions With a 4 kV anode bias and a peak current of several hundred amperes, the modified LIMS reduces the full-width-at-half-maximum of the current pulse from 0.79 µs to <100 ns and shortens the turn-off time to 0.6 µs. These results indicate suitability for repetitive operation at kilohertz frequencies and above.

     

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