LPCVD法在GaN上生长Ge薄膜及其特性

本文报道了在GaN/蓝宝石作衬底生长Ge薄膜材料的外延生长及其特性研究。研究了不同外延生长条件。结果表明,使用低压化学气相外延技术在GaN/蓝宝石衬底复合衬底上可以生长Ge薄膜。高分辨X射线衍射谱研究得到了峰位分别位于2θ=27.3°、2θ=45.3°和2θ=52.9°的Ge峰.原子力显微镜研究表明得到的Ge薄膜的表面粗糙度为43.4nm。扫描电子显微镜研究表明生长的Ge/GaN/蓝宝石具有清晰的层界,表面Ge晶粒致密并且分布均匀。Raman谱表明所生长的Ge的TO声子峰位于299.6cm-1,这表明了生长的Ge薄膜具有良好的质量。

Growth and Characterization of Ge on GaN by LPCVD

The epitaxial growth of Ge on GaN/sapphire substrate is reported.Different growth conditions are tested.The authors found that growth of Ge directly on GaN/sapphire substrates produces good Ge films by low pressure chemical vapor deposition(LPCVD).High resolution X-ray diffractometry shows that three Ge peaks located at 2θ=27.3°、2θ=45.3° and 2θ=52.9°,rseparately.Morphologies of the layer were imaged with atomic force microscopy,which show that the roughness of the Ge film is 43.4nm.The photograph of the cross section of the sample by scanning electron microscopy shows clearly Ge/GaN/Al2O3 three layers.The Ge grains of the surface are dense and uniform.From the Raman spectra we obtain the strong Ge TO phonon mode peaks around 299.6cm-1.This means that we get good quality of Ge films.