Simulation Study On Silicon-based Blue-light Enhanced APD Detector For Visible Light Communication

With the rapid development of visible light communication,it is urgent to solve the problems of low responsivity and low quantum efficiency of silicon-based avalanche photodiodes(Avalanche Photo Diode,Si-APD)in blue wave region.In this paper,the simulation of Si-APD devices is studied by using ATLAS device simulation software.Based on the traditional silicon-based separate absorption and multiplication structure(SAM type Si-APD),this paper exchanges the absorption layer with the multiplication layer position to make the multiplier layer closer to the photosensitive layer,so as to achieve the purpose of blue light enhancement.Thus a new SAM-type Si-APD device with high responsivity and high quantum efficiency in the blue-light region is obtained.After the device structure is determined,the internal structure size and doping concentration are further optimized,so that the responsivity of APD devices at 450nm is increased from the original20.9A/W to 30.5A/W,and the quantum efficiency is also increased from 57.68%to 84.18%.At the same time,the peak response of APD devices is also increased from 33.7A/W to 39.8A/W.Finally,on the basis of the optimized structure,the SiO₂ passivation layer and diffusion protection ring are added to both ends of the APD device,which further improves the responsivity and quantum efficiency of the APD device and the voltage resistance of the device as a whole.The APD simulation design in this paper reduces the blindness and the experimental cost of the device fabrication,and provides the design basis for the actual device fabrication.