External-field-controlled laser wet etching of polycrystalline Al2O3TiC

Abstract

Laser-induced etching of polycrystalline Al2O3TiC material by tightly focused CW Ar ion laser has been investigated in both H3PO4 and KOH solutions with influence of an external electric field. It is found that a weak external electric field will change the ions distribution in chemical solutions and cause obvious change in etching behavior. The laser etching in a H3PO4 solution can be enhanced by both positive and negative biases of the substrate. While etching in a KOH solution, a positive bias can enhance the etching reaction, whereas a negative bias can suppress the etching process. It is also found that the external electric field can always enhance the mass transfer between reaction products and fresh etchant in a H3PO4 solution. It is revealed that the supply of H+ ions contributes to the etching process in a H3PO4 solution, while the supply of OH- ions contributes to the etching process in a KOH solution. The electric field can be used to control the etching process to achieve fast tuning and higher accuracy.