Selective wet-etching of undoped and silver photodoped amorphous thin films of chalcogenide glasses in inorganic alkaline solutions

Abstract The unexposed/exposed, Ag-rich (exposed)/Ag-poor (unexposed) and amorphous (unexposed)/crystallized (exposed) parts of vacuum evaporated amorphous chalcogenide films of composition As 33 S 67 , As 33 S 50 Se 17 , As 33 S 33.5 Se 33.5 , As 33 S 17 Se 50 , As 33 Se 67 , Ag x (As 33 S 67 ) 100− x and Ag x (As 33 S 33.5 Se 33.5 ) 100− x were selectively etched in water solutions of inorganic alkaline substances (NaOH, Na 2 S, (NH 4 ) 2 S, Na 2 CO 3 and NaCN). Different etching rates for exposed and unexposed parts were found depending upon the sample composition, type of etchant and its concentration. A resolution coefficient, γ , was confirmed by selectively etched films after their exposure through a gray-scale photomask with microlenses array motives.