Study On The Key Technology Of The Black Silicon Optoelectronic Detector

As the manufacturing technology of black silicon is becoming more and more consummate,the material gradually shows more and more potential in the field of photoelectric detection,because of its excellent light trapping property,wide spectrum absorption,cheap manufacturing cost and good process compatibility.The key technology of black silicon photoelectric detection is to combine the unique properties of black silicon and the design of detectors,and integrate material performance research,device structure design and manufacturing process.Based on the basic theory of optoelectronics and starting from the theoretical research of black silicon characteristics and the practical production of black silicon photodetectors,we have explored the key technologies of material performance,device structure and fabrication process of black silicon photodetectors.Based on the manufacturing technology of black silicon,a new method of establishing physical model of black silicon based on random number generator is proposed.Based on the established energy band model and surface microstructure model of black silicon,the specific influence of black silicon’s energy band structure and surface microstructure on its performance is analyzed.In this paper,an innovative research method for analyzing the internal optical transmission process in black silicon microstructures is presented and the process is calculated and analyzed.A PtSi/Black Silicon Schottky junction was introduced on the back side of silicon substrate by means of gold assisted etching and magnetron sputtering.Based on the standard device processing flow,PtSi/Black Silicon Schottky photoelectric detector was fabricated,and the key performance parameters of the detector were tested and analyzed.The final conclusions are as follows:1.The unique microstructures of black silicon and its band structure filled with impurity energy levels determine the wide spectrum and high absorption characteristics of black silicon.The micro structure produces light trapping effect and reduces reflectivity.The energy band structure reduces the electron transition energy so as to increase the absorbing ability.2.In the surface microstructure of black silicon,the microstructural parameters change the absorption characteristics of black silicon by changing the effective absorption thickness of black silicon（the length of light path propagating inside the black silicon）,and the larger the effective absorption thickness is,the stronger the absorption is.3.The angular distribution of the light in the black silicon increases the effective absorption thickness of the material,and indirectly increases its absorptive capacity.4.The PtSi/black silicon microstructures have strong photon absorption and photogenerated carrier generation ability in a wider spectrum range.5.The spectral response range of the PtSi/black silicon Schottky type photoelectric detector is from 400 to 2500nm and the peak responsivity of the detector reaches to10.5A/W（@1064nm,0.5V,schottky junction reverse bias）.The peak quantum efficiency reaches to 100%（@800nm）.The dark current is around 15nA and the response time is less than 10ns.The normalized detectivity is calculated to be1.79×10¹³cm?Hz^1/2?W^-1.6.The Schottky photodetector based on PtSi/black silicon microstructures has a wider spectral response range and a higher responsivity than conventional silicon based photodetectors,and is expected to have high detection performance at room temperature.