Charge Imbalance Tolerance of 4H-SiC Superjunction Devices Featuring Breakdown Path Variation
Charge Imbalance Tolerance of 4H-SiC Superjunction Devices Featuring Breakdown Path Variation
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DOI：
10.1109/led.2023.3281328
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发表时间：
2023-07
影响因子：
4.9
通讯作者：
Xuan Li;Lingfeng Li;Kunze Xie;Zhengyu Yang;Wenguang Wu;Xiaochuan Deng;Bo Zhang
中科院分区：
文献类型：
--
作者：
Xuan Li;Lingfeng Li;Kunze Xie;Zhengyu Yang;Wenguang Wu;Xiaochuan Deng;Bo Zhang
本文深入研究了电荷不平衡对碳化硅超结器件的影响。通过对SiC碰撞电离各向异性和电荷不平衡SJ二维电场分布的联合分析，首次揭示了不同电荷不平衡程度下的击穿路径变化。主要由于这种各向异性，重要的发现是，当P柱或N柱稍微欠掺杂时，击穿电压甚至可以高于平衡情况。在此基础上，提出了一种基于FOM灵敏度和工艺容差的SJ设计方法，为在一定的电荷不平衡度范围内更好地设计低灵敏度SJ器件提供了指导。结果表明，宽的支柱，建议大的工艺公差和欠掺杂的情况下，是不敏感的电荷不平衡比过掺杂的情况。简而言之，上述启示可以获得对各种电荷不平衡SJ情况的新的物理水平的见解，并且该方法不仅可以实现基于实际工艺能力的高FOM，而且还可以实现基于目标性能的所需工艺公差。
In this letter, the impact of charge imbalance on silicon carbide (SiC) superjunction (SJ) device is studied thoroughly. The breakdown path variation under different degrees of charge imbalance is revealed for the first time by joint analysis of the SiC anisotropy of impact ionization and the charge-imbalanced SJ two-dimensional electric field distribution. Primarily due to this anisotropy, it is a significant finding that the breakdown voltage could be even higher than the balance case when either P or N pillar is slightly under-doped. Furthermore, an SJ design methodology is proposed based on figure-of-merit (FOM) sensitivity and process tolerance, which guides how to better design low-sensitivity SJ devices within a certain range of charge imbalance degree. It is indicated that the wide pillar is suggested for large process tolerance and the under-doped case is less sensitive to charge imbalance than the over-doped case. In brief, the aforementioned revelation can gain new physics-level insights into various charge-imbalanced SJ cases and the methodology can achieve not only the high FOM based on practical process capability but also the required process tolerance based on target performance.