离子注入减小条形射线探测器表面漏电的研究

REDUCTION OF LEAKAGE CURRENT OF STRIP RADIATION DETECTOR BY A SIMPLE CAP IMPLANTATION

选择高阻N型〈10 0〉单晶硅材料 ,X射线探测器为PIN管结构 .为了减少器件表面缺陷对暗电流的影响 ,在器件P区的两侧使用离子注入形成浅层低浓度N区 ,以减小器件的暗电流 .通过对比实验发现 ,当N区的注量增大时 ,在相同反向偏压条件下 ,器件的暗电流密度随之减小 ,同时击穿电压也相应减小 .为了减小器件的工作电压并进一步减小工作时的暗电流密度 ,还将器件的背面进行厚度减薄、抛光和AuSb/Au合金形成欧姆接触 .对减薄后的器件进行I V特性测量 ,由于工作电压大幅降低 ,器件正常工作时的暗电流密度大幅度减小 .同时在实验中发现温度对暗电流的影响非常大 ,将器件温度降低到 - 15℃时 ,暗电流密度可降低到 1nA·mm- 2 以下 .

A X-ray detector with PIN structure is fabricated on high-resistivity, n-type <100> single crystal silicon. To reduce dark current, N protection regions are made on both sides of P regions by low concentration shallow ion implantation. At the same reverse-voltage, the dark current of the detector decreases with increasing quantity of implants in N protection regions. Surface smoothing, back-side thinning and AuSb/Au ohmic contact are adopted. I-V curres are obtained for thinned detector at different temperature.