Technology and properties of magnetron sputtered CuInSe2 layers

Variance of direct-current magnetron sputtering from a multi-sector target as a new method for direct synthesis of multicomponent layers is described. It has been shown that a precise control of the chemical composition of the layers can be achieved. As an example, CuInSe2 films have been deposited on different substrates (glass, KCl, Mo) using a special three-component target. The characteristics of the films have been studied by X-ray diffraction (XRD), infrared spectroscopy, electrical measurements and positron annihilation spectroscopy. The XRD data showed that all films are crystalline and the presence of the sphalerite CuInSe2 only. The reproducibility of the chemical composition of the layers has been examined by atomic absorption analysis. The electrical resistivities are in the range (2–4)×10−3 Ω cm. It has been suggested that a crystallographically monophase sample could be an electronically bi-phased one when the effective carrier Bohr radius is smaller than the Debye length and if their drift free path is larger than the Debye length. Positron annihilation spectroscopy indicated the presence of monovacancies and small vacancy clusters. In the studied layers small vacancy clusters and positronium atoms are formed. The X-ray data show that no phase transition occurs in the CuInSe2 phase from room temperature to 400 °C.