Etching Kinetics of III–V Semiconductors Coupled with Surface Passivation Investigated by Scanning Electrochemical Microscopy

Because of their unique physical and electric properties and chemical stability, the etching kinetics of III–V semiconductors is of great significance in the fabrication of functional microdevices. However, the produced oxides result in a surface passivation and hinder the etching progress. Taking into account the passivation and depassivation of the insoluble oxides, we investigated the etching kinetics of III–V semiconductors (i.e., n-GaAs, n-InP, and n-GaP) by scanning electrochemical microscopy (SECM) as well as the finite element method. By considering the coupling effect of the mass transport process and surface reactions, a dynamic deformed geometry module was adopted to determine both the etching rate and passivation rate individually and further correlate the kinetic parameters to the topography of the etching pits. The results show that the etching process will be slowed or will even cease with increasing kinetic rate of surface passivation. On the basis of the component analysis of the passivat...