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采用分子束外延方法在GaAs(001)衬底上生长了InSb外延薄膜,其中采用“二步法”制备了不同厚度的低温InSb缓冲层结构。利用Mullins扩散模型对缓冲层的生长过程进行了具体演化。结合扩散模型的计算结果,通过原子力显微镜以及透射电子显微镜研究了InSb缓冲层表面的波纹结构对后续InSb薄膜生长的影响规律。研究表明,适当的缓冲层厚度有利于InSb薄膜的外延生长,缓冲层厚度超过60 nm后,InSb薄膜表面的粗糙度明显增加,引人了大量位错导致外延薄膜的电性能下降,采用“二步法”生长30~50 nm厚的InSb缓冲层比较合适。
InSb epitaxial films were grown on GaAs (001) substrates by molecular beam epitaxy. The low temperature InSb buffer layers with different thicknesses were prepared by the “two step method” method. Mullins diffusion model was used to analyze the growth of buffer layer. Combined with the calculation results of the diffusion model, the effect of the ripple structure on the growth of subsequent InSb thin films was investigated by atomic force microscopy and transmission electron microscopy. The results show that the appropriate thickness of buffer layer is favorable for the epitaxial growth of InSb thin films. The roughness of the InSb thin films increases obviously when the thickness of the buffer layer exceeds 60 nm, and the electrical properties of the epitaxial thin films are induced by a large number of dislocations. Two-step method "growth 30 ~ 50 nm thick InSb buffer layer is more appropriate.