In this article, we focus on the physical modeling of the nonlinear operation of intrinsic photoconductive semiconductor switches (PCSS) based on 4H-SiC using coupled electrical and optical simulations to provide performance bounds of the switch as a function of material and geometry parameters, as well as applied bias. We also conduct a full design-space exploration to identify the optimal operating and design conditions to maximize the compound metric fopPout, where fop is the maximum operating frequency, and Pout is the maximum output power the switch can provide. We quantify that a 10-μm long and 5-μm thick 4H-SiC PCSS can deliver output power density greater than 2W/mm at 150 GHz when triggered by a 0.325-μm laser with intensity of 3 kW/cm2. The output power density can be significantly enhanced by increasing the optical generation rate as well as by using thicker SiC to improve its absorption characteristics. A brief discussion of signal distortion and electrostatic screening effects at high optical bias is included. Finally, we present an analytic model of charge cloud propagation and the frequency of operation based on the physics, material parameters, and geometry of the PCSS. The model accurately captures fop of 4H-SiC PCSS over a broad range of laser spot size, device length, and electrical bias applied at the contacts.

中文翻译：

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适用于高功率和高频应用的碳化硅光电导开关的性能建模


在本文中，我们重点关注基于 4H-SiC 的本征光电导半导体开关 (PCSS) 的非线性操作的物理建模，使用耦合电学和光学模拟来提供开关的性能范围作为材料和几何参数的函数，如下所示以及施加的偏压。我们还进行了全面的设计空间探索，以确定最佳操作和设计条件，以最大化复合指标 fopPout，其中 fop 是最大工作频率，Pout 是开关可以提供的最大输出功率。我们量化了，当由强度为 3 kW/cm2 的 0.325 μm 激光触发时，10 μm 长、5 μm 厚的 4H-SiC PCSS 在 150 GHz 下可提供大于 2W/mm 的输出功率密度。通过提高光发生率以及使用更厚的SiC来改善其吸收特性，可以显着提高输出功率密度。简要讨论了高光学偏置下的信号失真和静电屏蔽效应。最后，我们提出了基于 PCSS 的物理、材料参数和几何形状的电荷云传播和操作频率的分析模型。该模型可在各种激光光斑尺寸、器件长度和接触点上施加的电偏压下准确捕获 4H-SiC PCSS 的 fop。