MECHANISTIC STUDY OF SILICON ETCHING IN HF-KBRO3-H2O SOLUTION

The chemical etching of silicon in HF-KBrO3-H2O mixed solution has bee n investigated experimentally. The etch rates were examined with varyi ng HF and KBrO3 concentrations, agitation speed, and etching temperatu re. The etch rates were similar for both n- and p-type Si(100). HF pla yed an important role for accelerating the formation rate of holes at the silicon surface and the removal rate of K2SiF6 formed on the wafer surface during the reaction. A comprehensive mechanism for the surfac e species formation and the silicon etching as a function of etchant c oncentration was developed. The holes formed at the silicon surface ac celerated the etch rate and the formation of the K2SiF6 layer. For hig h HF concentration, we suggest that the rate-determining step of the r eaction was the formation of holes at the silicon surface.