Research On Current Automatic Control Technology In N-type Macroporous Silicon Photoelectric Chemical Etching

In this paper, n type macro porous silicon photoelectric chemical etching mechanism was introduced, and the corresponding relationship between corrosion current and aperture was studied. The results shows that when the critical current density, aperture with the etching current increases. The influence factors of critical current density were analyzed. The size of the critical current density affected by external factors such as temperature and concentration of HF acid were founded, it will further influence the size of the aperture. Because of the etching current is controlled by light intensity, In this paper, the automatic control method of macro pore diameter by adjusting the light intensity was proposed, and the current automatic control system hardware and software was designed. In hardware design, the current control module adopts with the method of PWM drive BUCK circuit adjustment of lattice arrangement of LED lights; the temperature module IR2111was used to drive TEC for temperature control. In software design, the LabVIEW software design platform was applied, upper computer automatic control system includes serial communication, data conversion, data processing and display module were designed. Through the experiment verification, this system can prepare silicon with different aperture of macro pore by adjustment etching current.