Enhancing Near-infrared Sensitive In Silicon-based APD Four-quadrant Detector

With the development and application of optical detection technology,the demand for detection of photons in the near-infrared,especially in the 1064 nm,becomes more and more urgent.The enhancing near-infrared sensitive silicon APD quadrant detector is a photodetector based on the avalanche multiplication effect,and is widely used in the fields of photoelectric tracking,and laser alignment.Compared to ordinary silicon PIN four-quadrant detectors,it has fast response,high sensitivity,wide spectrum detection range.This class describes the device structure and working principle of an avalanche silicon photodiode four-quadrant detector,and introduces important characteristic parameters such as photo responsivity,temperature coefficient,breakdown voltage,crosstalk,and black silicon?The Ge/Si heterojunction technology is described in detail.Based on the theoretical research,firstly,the enhancing near-infrared sensitive structures such as the front microlens array,the back-faced texturing,and the anti-reflection coating used in the developed device were analyzed and simulated.The simulation software was used to build the device simulation model.According to The formula and device simulation model calculates the process parameters,the device process parameters and the simulation process parameters matched each other.Then,during the process of describing the manufacturing process of the device,the difficulties in production were analyzed,and a solution was proposed.Finally,in the tests,it was confirmed that the device performance parameters meet the project requirements.The main research results show that:First,Based on the research of device,the structure of AR coatings is as follows:passivation layer SiO₂?40nm?+passivation layer Si₃N₄?100nm?+microlens material LTO?12000nm?+surface Si₃N₄?225nm?+The surface SiO₂?200 nm?has a transmittance of>95%in the 1064 nm.Second,Using Zemax optical simulation software,based on the principle of geometrical optics,the microlens condenser light path and the focal plane energy distribution?wavelength of the light source 1064nm?were simulated.Through calculation,it was obtained that the diameter of the microlens was 14?m and the focusing distance was 10?m.The amount of light is>90%.At last,The single-crystal silicon wafer with the resistivity of 2500-5000?·cm was used for etching on the backside microstructure.The optimum ratio of the etching solution was?HNO₃:H₂O:HF?=4:5:1.At this time TTV<6?m,the reflectivity<2%.The device developed in this article uses a unique dark current suppression technology,anti-pixel crosstalk technology,near infrared enhancement technology,in the comparison test.The initial response of the near-infrared at the 1064 nm?without multiplication?reached 0.42 A/W,and the dark current is 5¹0nA,which are better than those of the first sensor company in Germany.