Etching of semiconductors by products of laser thermal dissociation of molecular gases

An experimental investigation was made of a new possibility of initiation and control of heterogeneous chemical reactions by laser radiation in the specific case of the etching of semiconductors (Ge, Si, GaAs, ZnSe) by halogens (I, Br). Chemically active particles were generated by purely thermal dissociation of molecules containing halogens (CF₃I, Br₂) mixed with a thermal sensitizer (SF₆) and subjected to CO₂ laser radiation. A high spatial selectivity of the etching process was achieved. An experimental study was made of the optimal conditions for the etching of germanium, the final products of the chemical reactions in the gaseous medium and on the etched surface of germanium were analyzed, and a model of the processes occurring in the course of etching was proposed.