退火La_2O_3薄膜表面形貌的演化与分析

Characteristics and Analyses of Surface Morphologies of Annealed La_2O_3 Thin Films

为了研究退火温度对电子束蒸发法沉积的LaTiO_3薄膜晶体结构的影响,使用X射线衍射仪对薄膜晶体结构进行表征,采用扫描电子显微镜和光学显微镜对退火处理后的薄膜表面形貌进行了表征.使用图像二值化方法对薄膜晶化过程中产生的分形花样进行了采样,并通过分形计算获得了分形维数及多重分形谱,从而分析了不同退火温度下薄膜晶化特点.结果表明:随着退火温度的升高,非晶La_2O_3薄膜发生六方相形核长大和立方相形核长大两种不同的晶化过程,并且在立方相形核长大过程中伴随着分形结构的产生,薄膜在850~900℃之间存在两种相的形核转变点.

For investigating the effect of annealing temperature on crystalline structure of La_2O_3 thin film deposited by the electron beam evaporation method,surface morphologies and crystalline states of annealed La_2O_3 thin films were characterized by SEM,OM and XRD.It was found that fractal patterns presented on the surfaces of crystalized films with cubic phase.The relationship between the temperature of the annealing process and the characteristic of the resulting surface morphology was examined by the fractal computation.The fractal patterns were sampled by the method of image binarization.Fractal dimension and multifractal spectra were calculated.It was showed that the effect of annealing temperature on the width of spectrum and theΔf was apparent.Combining with XRD results,it was determined that in the range of 850 to 900 ℃there is a critical temperature,above which the growth of the cubic phase was over the one of hexagonal phase.