像素探测器一直是高分辨率、高速率粒子跟踪的工作平台。本文以多晶硅/氧化硅(poly-Si/SiOx)钝化接触异质结结构设计了硅像素探测器,为了实现探测器的超快响应,采用Silvaco TCAD对异质结硅像素探测器进行器件仿真,一方面研究了不同衬底厚度对载流子输运和收集的影响,另一方面研究了器件结构设计对异质结像素探测器击穿电压的影响。仿真结果表明:在相同的偏置电压下,较薄的硅衬底可以获得更强的漂移电场,进而提高器件对信号电荷的输运与收集速率,有利于提高探测器的时间响应。较小的保护环-有源区间距有利于提高器件的击穿电压,而在保护环-有源区间距较大的情况下,在有源区边缘设计金属场板结构,也能够有效提高器件的击穿电压,使探测器可以工作在较高电压下,从而提升探测器的响应速率。

Pixel detector has always been the working platform of high-resolution and high-speed particle tracking.In this work,silicon pixel detector based on poly-Si/SiOx passivating contact heterojunction structure was designed.In order to obtain fast response of the pixel detectors, device simulation was performed using Silvaco TCAD.The influence of substrate thickness on the transportation and collection of signal carriers was studied. Meanwhile,the effect of device structure on the breakdown voltage of detectors was also researched.The simulation results showed that a stronger drift field can be built for the thinner substrate given the same bias voltage,thus a better carrier transportation and collection can be achieved,it helps to improve the time response of detectors .A narrow gap between the active region and the first guard ring was helpful for increasing the breakdown voltage.In the case of wide gap between the active region and the first guard ring, the breakdown voltage can also be improved by designing a field plate structure on the edge of the active region.As a result, the pixel detector can work under a large bias voltage and a fast response can be realized.

国家重点研发项目(2020YFB1506503,2018YFB150050,2018YFB1500200)、国家自然科学基金(62074165,12035020,52072399)和北京市自然科学基金(4192064,1212015)资助项目