Theoretical Simulation Study Of Charge Collecting Efficiency For Electron Bombarded Active Pixel Sensor

Electron Bombarded Active Pixel Sensor(EBAPS)has received special attention in the field of low light level imaging at home and abroad with its high detection sensitivity,high mechanical and electrical integration,low power consumption,small size,low cost CMOS process,etc..Because the performance of EBAPS is affected by the electron multiplying layer structure parameters,so in this article the theoretical simulation research to the relationship between electron multiplier layer structure and charge collection efficiency was studied.Firstly,according to the method that interaction mode of low-energy and electron-solid combined with Monte Carlo,the electron scattering characteristics are simulated and analyzed when electrons are incident in the sample.Secondly,the distribution of the multiplied electrons are simulated when electrons are incident in the multiplied layer of EBAPS,the distribution model of the multiplied electrons in the multiplier layer is established,and the trajectory distribution of the multiplied electrons is obtained.At last,under the circumstances of the substrate uniformly doped and substrate gradient doped the computational models for charge collection efficiency(CCE)of electron bombarded active pixel sensor(EBAPS)are established.In the case of substrate uniformly doped and according to the basic theory of the semiconductor,we have respectively studied the effects on the charge collection efficiency with different doping concentration,film thickness and incident electron energy.The theoretical simulation results of charge collection efficiency are in good agreement with the reported experimental measurements have been reported(4KeV,uniformly doped).At the same time,in the case of index doped,we studied the charge collection efficiency with different doping models,eventually,we obtained a higher charge collection efficiency of92%.The simulation research results of this study can provide theoretical guidance for the fabrication of high gain EBAPS.