Performance Limit and Design Guideline of 4H-SiC Superjunction Devices Considering Anisotropy of Impact Ionization
Performance Limit and Design Guideline of 4H-SiC Superjunction Devices Considering Anisotropy of Impact Ionization
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DOI：
10.1109/led.2022.3212465
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发表时间：
2022-12
影响因子：
4.9
通讯作者：
Changwang Wang;Xuan Li;Lingfeng Li;Xiaochuan Deng;Wentong Zhang;Liu Zheng;Yansheng Zou;W. Qian;Zhaoji Li;Bo Zhang
中科院分区：
文献类型：
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作者：
Changwang Wang;Xuan Li;Lingfeng Li;Xiaochuan Deng;Wentong Zhang;Liu Zheng;Yansheng Zou;W. Qian;Zhaoji Li;Bo Zhang
超结（SJ）结构是提高单极电源器件的比导通电阻（${R}_{\text {on,sp}}$）和击穿电压（$\textit {BV}$）之间的性能极限的最有效方法之一，特别是在高压和大电流区域。本文获得了兼具二维电场和4H-SiC冲击电离各向异性的4H-SiC SJ漂移区${R}_{\text {on,sp}}-\textit {BV}$性能极限。击穿路径为N柱底部中点经P-N柱界面中点到P柱顶部中点的曲线，而不是沿柱中线，这是因为沿[$11~\overline {{2}}~0$]的冲击电离比沿[0001]的冲击电离强。并给出了在一定$\textit {BV}$条件下优化${R}_{\text {on,sp}}$ （${R}_{\text {on,opt}}$）的设计准则，包括SiC SJ漂移区宽度、深度和浓度。采用SJ使得SiC漂移区${R}_{\text {on,sp}}$与$\textit {BV}$（即${R}_{\text {on,sp}}\propto \textit {BV}^{{1.007}}$）具有准线性关系，TCAD仿真很好地验证了这一点。当$\textit {BV}$大于2000V时，SJ利用率可以显著降低SiC器件的${R}_{\text {on,sp}}$。通过击穿路径的确定，理论性能极限显示了SJ方法在高压大电流SiC器件中的巨大潜力，实际设计指南可以指导更好地设计SiC SJ器件。
Superjunction (SJ) structure is one of the most effective approaches to improving the performance limit between specific ON-resistance ( ${R}_{\text {on,sp}}$ ) and breakdown voltage ( $\textit {BV}$ ) for the unipolar power device, particularly in high-voltage and high-current areas. In this letter, ${R}_{\text {on,sp}}-\textit {BV}$ performance limit of 4H-SiC SJ drift region is achieved featuring both the two-dimensional electric field and the anisotropy of impact ionization of 4H-SiC. The breakdown path is the curve from the bottom midpoint of N pillar to the top midpoint of P pillar via the midpoint of P-N pillar interface, instead of the midline of the pillar, due to that the impact ionization along [ $11~\overline {{2}}~0$ ] is stronger than that along [0001]. Moreover, a design guideline is provided for optimized ${R}_{\text {on,sp}}$ ( ${R}_{\text {on,opt}}$ ) under a given $\textit {BV}$ , including the width, depth, and concentration of SiC SJ drift region. SJ adoption enables SiC drift region to have a quasi-linear dependence of ${R}_{\text {on,sp}}$ on $\textit {BV}$ , i.e., ${R}_{\text {on,sp}}\propto \textit {BV}^{{1.007}}$ , which is well verified by TCAD simulation. With $\textit {BV}$ larger than 2000V, the SJ utilization can significantly reduce ${R}_{\text {on,sp}}$ of SiC device. By determining the breakdown path, the theoretical performance limit shows huge potential of SJ approach for the high-voltage and high-current SiC device, and the practical design guideline can instruct to better design the SiC SJ device.