Effect of etchant concentration and defects on pyramid formation in TMAH etched silicon

An investigation on the effect of TMAH concentration on the etch rate of si licon, and the influence of etchant concentration, ambient temperature and wafer thermal history on the formation of pyramids at the surface of TMAH e tched silicon has been carried out. From the results obtained from this stu dy, we are able to explain the influence of TMAH concentration and ambient temperature on the silicon etch rate and the changes occurring at the silic on surface satisfactorily using the pH theory. However, the results from wa fers with different thermal history seem to favour the defects theory. We s uggest that in order to explain the etching mechanism of TMAH of silicon sa tisfactorily, a combination of pH and defects theories is necessary.