Sequential Sputtering/Selenization Technique for the Growth of CuInSe2 Thin Films

Abstract

We have proposed a sequential sputtering/selenization technique and apparatus for the growth of CuInSe₂ (CIS)-based thin films. The apparatus consists of a cylindrical rotating drum for holding substrates and three horizontally interconnected subchambers for Cu, In, and Se fluxes. The serious problem associated with hybrid sputtering of metal target contamination by Se flux has been greatly reduced by the current geometric design. In this method, a very thin Cu/In stacked layer is first sputter-deposited, and then selenized with thermally evaporated Se vapor at each rotation of the drum. Polycrystalline CIS films for solar cells were grown by sequentially repeating these steps, which prevented the formation of the micron-sized voids usually observed in CIS-based thin films grown by selenization.