Research On Surface Processing Technology Of InSb Detector Chip

InSb infrared detector?InSb?can work in the wavelength range of 3⁵um,it has wide applications in the field of military and civilian medium wave infrared detection and imaging.The thickness of InSb,the surface roughness,the oxide of Sb and In seriously affect the quantum efficiency and dark current of detectors.Surface treatment technology,including surface grinding process and back lapping process,it has always been the key technology of InSb infrared detector,especially for the fabrication of large area focal plane,and it is also an important factor restricting the performance of detector.First of all,the technology of mechanical polishing on the surface of infrared detector is studied.Variety of factors affecting the surface quality of the wafer after grinding and polishing,the influences of pressure,speed,ratio of polishing material and dropping speed on the appearance of InSb were analyzed.The results show that the InSb surface with uniform thickness,smooth surface and few lattice defects is obtained when the abrasive ratio is 1:2,the pressure is 9 N,and the speed is 60 r/min,and the problem of bright spot are discussed at the same time.It was found that when the pressure is lower than 4.5 N,the speed is lower than 80 r/min,the ratio of polishing material is 1:1,the dropping speed is less than 1 drops/s or the oxidant H₂O₂ is added,the“bright spot”on the surface of the InSb chip has been effectively resolved.Secondly,the corrosion process of InSb wafer is studied in this paper.A new type of AB corrosion solution has been developed on the basis of traditional corrosion liquid.It can effectively remove the damaged layer after polishing,with smooth surface and no corrosion pit.In addition,the crystal structure and Micromorphology of the surface after fine throwing and wet processing were analyzed by X ray diffraction and atomic force microscopy.The results showed that the half peak width of the diffraction peak decreased from 0.054 degrees to 0.017degrees after the finishing,and the half peak width and the surface roughness decreased obviously after different wet methods,and the half peak width of the AB corrosion solution was half wide.At 0.0053 degrees,the surface defects are less,the lattice is complete,and the surface roughness is only 30nm.The PN junction infrared diode is made by the optimized grinding and etching process.The I-V characteristic test results show that the leakage current is obviously reduced.The R₀A is 8.16×10²?·cm² and the blackbody detection D*is 3.1×10¹⁰ cm·Hz^1/2·W^-1.In this paper,the lapping process of InSb focal plane detector is studied.First,the traditional process of mechanical lapping and simplex chemical corrosion thinning is carried out.The results show that the traditional mechanical lapping appears a lot of cracks when thickness to 30 um is caused by the high stress,and the chemical corrosion of pure HF acid and HNO₃ acid can be caused by the difference of corrosion rate.It causes rough surface or even about 100?m height difference.and after the optimization,the surface can not reach the ideal requirement,no imaging.With the combination of chemical corrosion and mechanical polishing,the stress crack and surface roughness of the material are solved.The prepared InSb focal plane detector is uniform in response and clear in imaging.