Chemical and microstructural study in radio frequency sputtered CdTe oxide films prepared at different N₂O pressures. Oxygen incorporation and film resputtering

CdTe oxide films were grown by radio frequency sputtering in Ar-N₂O plasma at different N₂O partial pressures. The film oxygen content determined by Auger electron spectroscopy ranged from 15 to 60 at.%. The free O₂ production during film deposition was monitored by in situ mass spectroscopy and it was found that it increases linearly over a critical N₂O pressure ~ 4.7 × 10^{- 3} Pa alike the oxygen in the films. Film microstructure was studied by Raman spectroscopy and atomic force microscopy. Evidence of bands related to terminal Te-O vibrations was found in films prepared below the N₂O critical pressure, becoming predominant in films with higher oxygen content. The morphology and roughness evolution of the films confirm that they consist of a mixture of phases. Surface structures of the Ia-type and of the Ib-type were observed below and above the critical N₂O pressure. Eventually, ion bombardment process caused film resputtering.