A novel deposition technique for compound semiconductors on highly porous substrates:: ILGAR

ILGAR (ion layer gas reaction), a novel low-cost technology for the preparation of sulfidic thin layers is described, which can be analogously applied for other chalcogenides. The process consists of three steps: (1) application of a precursor solution on a substrate by dipping or spraying, (2) drying in an inert gas stream, (3) sulfurization of the solid precursor (e.g. a metal halide) by hydrogen sulfide gas. This cycle is repeated until the desired layer thickness is obtained. Not only on smooth, but also on structured and porous substrates the method allows the deposition of homogenous thin films following the microscopic structure, where other methods often have problems with shading. Once the film is closed, the growth per dip cycle is constant and reproducible during the process. The binary compounds CdS, Cu2S, In2S3 and also the ternary CuInS2 have been prepared by ILGAR on glass and on porous TiO2 or SiO2. The layers were characterised by XRD, SEM and EDX. (C) 2000 Elsevier Science S.A. All rights reserved.