Sb-Te phases sputtered from an Sb2Te3/Sb/Te target in a substrate temperature range from 293 to 523 K are characterised by X-ray diffraction (XRD) and Hall measurements. A simple thermodynamic model is introduced for estimating the chemical stability of the Ni/Sb2Te3 and the Mo/Sb2Te3 interface. These data and the results of kinetic test reactions for sputtered Ni/Sb2Te3, Ni/Sb-Te, Mo/Sb2Te3 and Mo/Sb-Te layers are compared using XRD measurements. Metal/Sb2Te3 thin film double-layer systems are used as a model for an innovative back contact for CdTe/CdS thin film solar cells offering an improved long-term stability. (C) 2002 Elsevier Science B.V. All rights reserved.