EBCMOS中背散射电子的特性研究  

Characterization of Backscattered Electrons in EBCMOS

作　　者：吕蒙 宋德[1] 焦岗成 李野[1] 王连锴[1] 陈卫军 Lv Meng;Song De;Jiao Gangcheng;Li Ye;Wang Liankai;Chen Weijun(School of Physics,Changchun University of Science and Technology,Changchun 130022,Jilin,China;Science and Technology on Low-Light-Level Night Vision Laboratory,Xi′an 710065,Shaanxi,China)

机构地区：[1]长春理工大学物理学院,吉林长春130022 [2]微光夜视重点实验室,陕西西安710065

出　　处：《中国激光》2024年第17期137-144,共8页Chinese Journal of Lasers

基　　金：国家自然科学基金联合基金重点项目(U21B2061);国家自然基金联合基金叶企孙项目(U2141239)。

摘　　要：基于高能电子与固体间相互作用原理和蒙特卡罗模拟方法,模拟研究电子轰击互补金属氧化物半导体(CMOS)中背部减薄CMOS表面附近背散射电子的特性。主要研究背散射电子特性中的角分布(θ_(B)和Φ_(B))、背散射电子数与入射电子数之比(R_(BI))以及背散射电子与入射电子之间的距离分布(D_(BI)),并分析这些散射特性是如何受钝化层表面结构、入射电子能量、栅控电压和电子束直径的影响的。研究结果表明:增加钝化层密度有利于降低弹性碰撞的平均散射步长、入射深度和弹性散射半径,进而降低R_(BI);增加钝化层厚度可以减小背散射电子的出射范围D_(BI),使电子弹性散射集中在钝化层表面,从而减小R_(BI);入射电子束直径的改变对于R_(BI)没有较大的影响,但是D_(BI)最大值和入射电子束直径相差值都约为100 nm;选用与钝化层厚度匹配的入射电子能量,能获得较小的R_(BI);背散射电子特性中的角分布的情况基本不随上述变量变化而变化。若只考虑钝化层材料对R_(BI)的影响,则可选择Al_(2)O_(3)为钝化层,设定入射电子能量为4.5 keV,得到RBI最小为19.0%;若从器件栅控电压和背散射特性折中考虑的角度出发,选择Si_(3)N_(4)作为钝化层材料,设定入射电子能量为3.6 keV,R_(BI)最小可达21.2%。总之,EBCMOS背散射电子特性的研究将为高性能的EBCMOS器件的制备提供理论参考。Objective Electron bombardment complementary metal-oxide-semiconductor(EBCMOS)is a new type of external photoelectric conversion image enhancement device that can realize digital imaging of targets under very low illumination.Unlike traditional low-light imaging devices,EBCMOS has the advantages of a small sensor size and weight,high sensitivity and dynamic range,fast response,and high contrast and resolution.The structure of an EBCMOS is mainly composed of a back-side bombarded complementary metal-oxide-semiconductor(BSB-CMOS),photocathode,and vacuum tube.The photogenerated electrons directly bombard the BSB-CMOS under the action of a strong electric field applied between the photocathode and BSB-CMOS anode.The photogenerated electrons then multiply,and the secondary electrons are collected in the BSB-CMOS.When incident electrons are accelerated to bombard the surface of a solid,some of these electrons are scattered back into the vacuum region between the photocathode and BSB-CMOS due to their interaction with atoms in the solid.Under the action of the near-focused electrostatic field,these scattered electrons re-incident onto the BSB-CMOS,resulting in backscatter noise,which affects the stability of the temporal and spatial distribution of the incident electrons and in turn affects the performance of the EBCMOS.Methods Based on the principle of interaction between high-energy electrons and solids and the Monte-Carlo simulation method,this study simulated and studied the characteristics of backscattered electrons near the surface of BSB-CMOS during electron bombardment.We mainly studied the angular distribution(θ_(B)andΦ_(B)),the ratio of the number of backscattered electrons to the number of incident electrons(R_(BI)),and the distance distribution between the backscattered electrons and incident electrons(D_(BI)).We then analyzed how these scattering characteristics are affected by the surface structure of the passivation layer,energy of the incident electrons,gating voltage,and diameter of the electron beam.

关 键 词：微光夜视 电子轰击型互补金属氧化物半导体 背散射特性 弹性散射 

分 类 号：TN223[电子电信—物理电子学]