Selective dissolution of Agx(As0.33S0.67−ySey)100−x chalcogenide thin films

Thin films of As33S67, As33S33.5Se33.5 and As33Se67 prepared by vacuum thermal evaporation were selectively etched in alkaline organic solutions of amines i.e. 1,2-diaminopropane, morpholine, aminoethanol, cyclohexylamine, hexylamine, butylamine and propylamine. Dissolution rates v, resolution coefficients γ and surface quality are discussed and compared to recently published results of etching process in inorganic solutions of NaOH, Na2S and (NH4)2S. The resolution coefficients achieved in amine based solutions are by the order of magnitude higher than ones in inorganic etchants. Etching in organic solutions showed increase of the resolution coefficient and decrease of dissolution rate of exposed and unexposed film in the sequence of propylamine, butylamine, hexylamine and cyclohexylamine solution. The role of different type of amine on dissolution rate and resolution coefficient is discussed. The dissolution parameter γ is getting worse in the same type of solvent with increasing content of Se. The dissolution mechanism and relation between photo-structural change and dissolution behavior of films are proposed. New results of negative selective etching of Agx(As0.33Se0.67)100−x in NaCN are presented and compared with selective etching curves of recently published Agx(As0.33S0.67)100−x and Agx(As0.33S0.335Se0.335)100−x thin films. Potential application is shown in fabrication of ‘microlenses like’ motive into the Ag–As33S67 thin film.