Study On Structure Growth Mechanism And Rapid Electrochemical Preparation Of P-Type Porous Silicon Regular Arrays

Porous silicon obtained by micromachining monocrystalline silicon is a new material with wide application.It not only has excellent semiconductor characteristics,but also plays an important role in the fields of photoelectric sensors,gyroscopes,silicon microstructures,photoelectric electromechanical systems and biomedical medicine due to its large specific surface area,excellent biosensing performance and high aspect ratio.The porous silicon regular array structure is superior to ordinary random porous silicon due to its excellent anisotropy and uniform law consistency.In this paper,the pore growth model,rapid preparation and the effects of experimental parameters on P-type porous silicon regular array are systematically studied.The effect of etching current density HF electrolyte composition on the growth process of P-type porous silicon regular array was revealed.The influence of pre-etched parameters on P-type porous silicon regular array and its rapid preparation were studied systematically.The main research contents and innovations are as follows:Firstly,the preparation process of P-type porous silicon regular array is studied,the preparation of P-type regular pre-etched silicon wafer is explored,and the photolithographic parameters,mask material and the initial shape of pre-etched silicon wafer are selected and confirmed.The results show that P-type porous silicon regular array is successfully prepared by electrochemical etching on P-type regular pre-etched silicon wafers.P-type regular pre-etched silicon wafers were prepared by photography method on monocrystalline silicon,Si3N4 was used as mask material,and inverted pyramid structure was used as pre-etched pits.The initial aperture(1×1 μm,1.5×1.5 μm,2×2 μm)and initial pore spacing(2 μm,3 μm,4 μm)of array pits were confirmed.Secondly,the initial growth process of P-type porous silicon regular array structure was studied,the growth model of P-type porous silicon regular array structure was improved,and the influence of electrochemical etching parameters on the morphology and growth rate of P-type porous silicon regular array structure was revealed.The results show that the initial growth process of P-type porous silicon regular array can be divided into three stages,namely start-up stage and transition stage and pore formation stage.In addition,the effects of different pre-etched pit sizes and initial pore spacing on the morphology of P-type porous silicon regular array are studied.The results show that different preetched parameters have a great influence on the duration of the initial three stages of pore growth,and the time of different pre-etched silicon wafers entering the pore formation stage is different under the same conditions.Finally,the rapid electrochemical etching of P-type porous silicon regular array structure was studied when the initial array was 1.5×1.5 μm.The influence of etching parameters on the rapid electrochemical etching of P-type porous silicon regular array and the experimental rules were systematically studied.And the porous silicon regular array structure with high aspect ratio was successfully prepared at a high etching rate.In this paper,the preparation method of P-type porous silicon regular array and the preparation process of regular array pre-etched silicon wafer are selected and confirmed.The effects of preetched parameters on the etching current density and HF concentration of P-type porous silicon regular array were systematically studied,and the effects of experimental parameters on the rapid electrochemical etching of P-type porous silicon regular array structure and experimental rules were explored.The experimental data and theoretical basis for the study and preparation of P-type porous silicon regular array have been accumulated,and the blank of systematic study on the structure of P-type porous silicon regular array has been supplemented,and the further application of P-type porous silicon regular array in sensor medical and microelectronics has been laid a foundation.