Research On Double Quadrants Silicon Photoelectric Detector With Near Infrared Enhancement

Near-infrared photodetectors are playing an increasingly important role in the military and medical fields.High-response,low dark current,fast response,and low crosstalk high-performance near-infrared quadrant detectors are the general trend of infrared detection technology development.Silicon material is an ideal material for infrared detector materials because of its low cost,easy integration,and mature technology.Due to the limitation of the band gap and reflectance of single-crystal silicon materials,when developing high-performance near-infrared enhanced photodetectors based on silicon materials,the common method is to black siliconize the silicon materials.At present,the process of preparing black silicon using femtosecond laser etching is inadequate,and there are no reports of near-infrared enhanced silicon dual four-quadrant detectors based on black silicon materials at home and abroad.Therefore,this paper designs the device structure and preparation process A lot of research has been done on improvements,detector preparation and testing.The main content and main results obtained are as follows:(1)Through theoretical research and analysis of the working principle,performance indicators,performance influencing factors and other theories of near-infrared enhanced silicon dual four-quadrant photodetectors,it provides the modeling and simulation of the detector device,and the improvement and optimization of processing technology Theoretical basis.(2)Performances such as responsivity,dark current,response speed,crosstalk between quadrants are affected by the device structure of the detector.On the basis of theoretical research,this paper obtained the I layer thickness and isolation of the detector device by modeling and simulating the photoelectric integrated model of the near infrared enhanced silicon dual four-quadrant photodetector,combined with the actual situation of production and processing The optimal selection of design parameters such as groove width and bias voltage:N-type high-resistance silicon material is used as the substrate,the thickness of the I layer is 180?m,the width of the isolation groove is 100?m,and the operating voltage is 50V.(3)A preparation process of highly doped Se-doped black silicon material is proposed.Using a femtosecond laser to ablate the Se-coated silicon material under HF gas atmosphere can improve the photoelectric performance of the material before and after annealing The surface morphology,optical characteristics,and carrier concentration of the black silicon material prepared under different preparation conditions(scanning speed,laser power,gas pressure)were tested and analyzed.(4)Highly recessed Se-doped black silicon material prepared under the process conditions of scanning speed of 1mm/s,laser power of 2.5W,and HF gas pressure of 9×10~4Pa,the surface is uniformly distributed black cone shape Silicon array,after testing,the average absorption rate of this material in the 400nm-2200nm band is 96.81%;the average absorption rate after annealing is 83.12%.(5)The developed near-infrared enhanced silicon dual four-quadrant photodetector has been tested and the average cell responsivity is 0.528A/W(@1060nm),0.102A/W(@1180nm);the average cell dark current is 4.4nA;The average cell response time is11.3ns;the average cell junction capacitance is 5.9pF;and the average crosstalk rate is1.9%.It shows that the structural parameters of the device designed by the simulation of the detector model are ideal,and the optimization of the processing technology has played a positive role.The research goal of the near-infrared detector with high response,fast response,low dark current,and low crosstalk has been achieved.