A study of the effects of wet chemical treatment on the surface of monocrystalline silicon wafers

Abstract

In the course of the work, experiments on wet chemical treatment of single-crystal silicon wafers were carried out. Samples of monocrystalline silicon wafers after various stages of wet chemical treatment were obtained and the lifetimes of non-basic carriers in these samples were measured. In addition, we studied the effect of each step of dry cleaning on the properties of single-crystal silicon wafers, experiments were conducted to study the effect of various recipes for wet dry cleaning of silicon wafers on the lifetime of non-basic charge carriers and the reflection coefficient of light from the surface of the samples. A few recipes of the method of wet chemical processing was selected. Namely, the concentration of the etching solution and the etching time were changed in this technique, and then the samples were measured.The results of studies have shown that the increase in the lifetime of non-basic charge carriers in the plates begins with the etching stage of the disturbed layer, while the degreasing itself has no effect on the lifetime of non-basic charge carriers. Also, it was shown that an important role is played by the purification of the surface from metals and the final treatment in hydrofluoric acid. It was found that to achieve better etching results it is much more effective to increase the time of plate treatment in solution than the concentration of alkali.