单场限环结构的表面电场分布及环间距的优化

基于横向扩散与纵向扩散构成的冶金结边界为椭圆形这一特点,讨论单场限环结构表面电场强度的分布,给出表面电场强度、主结及环结分担电压的解析表达式。在纵向结深和掺杂浓度一定的条件下,根据临界电场击穿理论,讨论环间距的优化设计方法。单场限环结构主结环结间表面电场强度的绝对值曲线近似呈抛物线,最大电场位于主结处。随着环间距的增大,最大电场变大;随着横向扩散深度的增大,最大电场变小。环右侧最大电场也出现在结处,随着环间距和横向扩散深度的增加,最大电场均减小。在场限环结构中,当主结和环结在表面处的最大电场强度均等于临界电场强度时,击穿电压达到最大值,此时所对应的环间距为最佳环间距。

Distribution of Surface Electric Field and Optimization of Ring Spacing with Single Floating Field Limiting Ring Structure

Based on the elliptic shape characteristic of metallurgical junction boundary formed by lateral diffusion and vertical diffusion,the surface electric field distribution with a single floating field limiting structure is discussed.The analytical expressions about surface electric field intensity and voltage undertaken by main junction and ring junction are presented.According to the critical field approximation at breakdown for a cylindrical junction,the optical design way with ring spacing is researched.The curve of absolute value about surface electric field intensity between main junction and ring junction is approximately parabola.The maximum field is situated in main junction,maximum field increases with the increase of ring spacing and decreases with the increase of lateral diffusible depth.The maximum field on the right of ring junction decreases with the increase of ring spacing and lateral diffusible depth.When maximum field of main and ring junction are simultaneously equal to the critical electric field intensity,the breakdown voltage approaches the maximum value and the corresponding ring spacing is optimum.