HgI_2探测器的共面栅电极设计及有限元模拟优化

Coplanar-grid electrode design of HgI_2 detector with finite element simulation and optimization

多晶碘化汞膜正逐渐成为制备室温下X射线成像探测器的优异半导体材料.设计8组不同栅宽和沟宽的共面栅探测器电极结构,进而使用有限元软件ANSYS对其进行模拟分析,得到相应的电势分布.结果发现,结构E(栅宽为150μm,沟宽为500μm)的电极设计效果最佳.之后,进一步设计了2组电极结构,用以研究在不对称电极形状所导致的边缘效应影响下的电势分布,结果发现通过加宽边缘第二个栅极(结构N)可以实现优化共面栅电极设计的目的,从而降低边缘效应产生的影响.

PolycrystaUine mercuric iodide films are developed as new detectors in room temperature X-ray imaging. In this paper, 8 different electrode patterns are designed by varying the widths of grid and gap. Finite element analysis is used to simulate the potential distribution of the coplanar-grid detectors. The electrode design of pattern E, with width of grid 150 μm and width of gap 500μm, is the best. The influence of edge effects resulting from the unsymmetrical electrodes on the potential distribution is discussed. The geometry of electrodes for coplanar-grid detectors is optimized by widening the second grids near edges as shown in pattern N.