Heavily doped 4H-silicon carbide (SiC) epitaxial p-n junction diodes are fabricated, and their tunneling current under reverse-biased condition is investigated. Soft increase of the leakage current before avalanche breakdown is observed in the diodes with heavy reduced doping concentration. The temperature and electric field strength dependencies of the leakage current reveal that the leakage current is caused by a phonon-assisted tunneling process. An accurate parameter set for simulating the phonon-assisted tunneling current in 4H-SiC is obtained, which agrees well with the experimental results within a wide temperature range (100–500 K) regardless of the reduced doping concentration. In 4H-SiC p-n junction diodes, the Zener breakdown occurs at the maximum electric field strength of 5.7 MV/cm.

中文翻译：

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4H-SiC pn 结二极管中的隧道电流

制备了重掺杂 4H-碳化硅 (SiC) 外延 pn 结二极管，并研究了它们在反向偏置条件下的隧道电流。在雪崩击穿之前，在掺杂浓度大幅降低的二极管中观察到漏电流的软增加。漏电流的温度和电场强度依赖性表明漏电流是由声子辅助隧穿过程引起的。获得了用于模拟 4H-SiC 中声子辅助隧道电流的准确参数集，无论掺杂浓度如何降低，这都与宽温度范围（100-500 K）内的实验结果一致。在 4H-SiC pn 结二极管中，齐纳击穿发生在最大电场强度 5.7 MV/cm 处。