Preparation Of Nb:TiO₂Films And Study On Optical And Electrical Proerties

Transparent conductive oxide films(referred TCO)are a hot topic in semiconductor industry, they have excellent optical and electrical properties, such as high transmittance in the visible region, low resistivity, have been widely used in the area of flat panel displays, solar cells and so on. TCO films which can be mature prepared currently include ITO, FTO, AZO films, but they all have shortcomings difficult to overcome. NbiTiO2(referred NTO) films are newly discovered TCO films in recent years with the advantages of good conductivity, non-toxic and low cost, have broad application prospects, but people’s understanding about them is still not sufficient, the preparation technologies are also not mature, it is necessary to study NTO films.In this paper, we successfully prepared NTO films consisted of small uniform dense grains on glass substrates using APCVD method, studied the influence of reaction temperature, gas flow on films and explored the optimum process parameters and the gas flow control laws. Meanwhile, we studied the influence of heat treatment, on the film morphology, structure, and improvement to optical and electrical properties.The results show that:with the increase of reaction temperature, the grains of NTO films become smaller and the transmittance become better, but above550℃, due to the decomposition of precursor, films will not be uniform and dense, The optimum reaction temperature is500℃-550℃, it’s easy to deposit films consisted of small uniform and dense grains with high transmittance in the visible region. As the increase of TiCl4, the grains of films become smaller and more uniform and the transmittance becomes better, while the structure of the films will change from rutile to anatase phase; when the amount of TiCl4is fixed, with the increase of gas flow of NbCls, the grains of films will also become smaller and more uniform, and the thickness is reduced accordingly, meanwhile, the transmittance gradually increases; we can achieve the adjustment of Nb concentration by the control of gas flow. High vacuum annealing can significantly improve the crystal quality, compared to Nb:TiO2film without H2annealing and un-doped TiO2films after H2annealing, the electrical properties of Nb-doped Nb:TiO2film after H2annealing have been obviously improved.