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采用金属有机化学气相沉积(MOCVD)方法制备了不同Al组分含量的2μm厚Al_xGa_(1-x)N外延膜,通过透射电镜定性分析了外延膜中的位错和缺陷,通过高分辨X射线衍射试验对Al_xGa_(1-x)N外延膜进行ω/2θ扫描,结果显示外延膜为六方晶系纤锌矿结构,通过对对称面和非对称面的晶面间距进行修正精确计算了外延膜晶格常数,并由此对应变进行定量分析,四个不同Al组分的Al_xGa_(1-x)N外延膜样品的四方畸变值随Al含量的增大而逐渐减小,并且均小于零,在水平方向上均处于压应变状态。
A 2μm thick Al_xGa_ (1-x) N epitaxial film with different content of Al was prepared by metal organic chemical vapor deposition (MOCVD) method. The dislocations and defects in the epitaxial film were characterized by transmission electron microscopy. Diffraction experiments show that the epitaxial film is hexagonal wurtzite structure by scanning ω / 2θ of the Al_xGa_ (1-x) N epitaxial film. The epitaxial film is calculated by correcting the interplanar distance of the symmetry plane and the asymmetry plane The lattice distortion of the Al_xGa_ (1-x) N epitaxial films with four different Al compositions gradually decreased with the increase of Al content, and both were less than zero. In the horizontal direction are in the state of compressive strain.