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.