垂直GaN-SBD的场限环-场板复合终端结构设计

Design of Field Limiting Ring-Field Plate Composite Terminal Structure for Vertical GaN-SBD

垂直GaN-SBD需要采用终端结构缓解阳极边缘电场集中现象,进而提高击穿电压。场限环终端结构可有效实现上述功能,但消耗的芯片面积较大,降低了一定面积晶圆上器件的数量。针对这一问题提出了场限环-场板复合终端结构,利用场板分散场限环边缘的电场,从而在保持器件击穿电压的同时减少场限环数量,减小器件的面积。通过TCAD仿真系统地研究了场限环-场板复合终端结构对垂直GaN-SBD击穿电压及阳极边缘附近的电场分布情况的影响。仿真表明,当维持相同的击穿电压(1700V),复合终端结构所需的场限环数量可减少2个,终端面积减小16.47%,而且阳极边缘的电场强度明显降低。

Vertical GaN SBDs requires the use of terminal structures to alleviate the phenomenon of anode edge electric field concentration,thereby increasing the breakdown voltage.The field limiting rings terminal structure can effectively achieve the above functions,but it consumes a large chip area,reducing the number of devices on a certain area of wafer.A field limiting rings-field plate composite terminal structure has been proposed to address this issue,which utilizes the field plate to disperse the electric field at the edges of the field limiting rings,thereby reducing the number of field limiting rings and decreasing the device area while maintaining the breakdown voltage of the device.The influence of the field limit rings-field plate composite terminal structure on the breakdown voltage and the electric field distribution near the anode edge of vertical GaN SBD was systematically studied using TCAD simulation software.Simulation shows that when maintaining the same breakdown voltage(1700V),the number of field limiting rings required for the composite terminal structure can be reduced by 2,the terminal area can be reduced by 16.47%,and the electric field strength at the anode edge can be significantly reduced.