Thermochemical dry etching of single crystal ferrite by laser irradiation in CCl4 gas atmosphere

Single crystal ferrite has been etched by focused Ar⁺ laser irradiation in a CCl₄ gas atmosphere. The etched groove showed cracks due to thermal stresses when samples were etched by a laser vaporization process in a vacuum, while in a CCl₄ atmosphere, such cracks were not observed. An etching rate of 68 /s obtained for a thermochemical process by laser irradiation was four orders of magnitude higher than that for a wet chemical etching process. A high aspect (depth-to-width) ratio of up to 10 was obtained for etched grooves. Under specific conditions, bending of the groove and orientation dependence in etching rate were observed.