ZnO／AlN／Si（111）薄膜的外延生长和性能研究

用常压金属化学气相沉积法(MOCVD)在Si(111)衬底上制备了马赛克结构ZnO单晶薄膜。引入低温Al N缓冲层以阻止衬底氧化、缓解热失配和晶格失配。薄膜双晶X射线衍射2θ/ω联动扫描只出现了Si(111)、ZnO(000l)及Al N(000l)的衍射峰。ZnO/Al N/Si(111)薄膜C方向晶格常量为0.5195nm,表明在面方向处于张应力状态;其对称(0002)面和斜对称(1012)面的双晶X射线衍ω摇摆曲线半峰全宽分别为460″和1105″;干涉显微镜观察其表面有微裂纹,裂纹密度为20cm-1;3μm×3μm范围的原子力显微镜均方根粗糙度为1.5nm;激光实时监测曲线表明薄膜为准二维生长,生长速率4.3μm/h。低温10K光致发光光谱观察到了薄膜的自由激子、束缚激子发射及它们的声子伴线。所有结果表明,采用金属化学气相沉积法并引入Al N为缓冲层能有效提高Si(111)衬底上ZnO薄膜的质量。

The Growth and Properties of ZnO Film Grown on Si(111) Substratewith AlN Buffer by MOCVD

Monocrystalline ZnO films with mosaic structure are successfully grown on Si(111) substrate by atmospheric-pressure metal-organic chemical vapor deposition (MOCVD). Low-temperature AlN buffer layer is introduced between the films and substrate to protect the substrate from being oxidized and eliminate the thermal and crystals lattice mismatch. Only appear diffraction peaks of Si(111) plane, ZnO(000l) index planes and AlN (000l) index planes [including the (0002) and (0004) planes] in double-crystal X-ray diffraction 2θ/ω scanning curve. The lattice constant of C direction is 0.5159 μm, which indicates ZnO film is suffering from the tensile stress. The full wide of half maximum (FWHM) of ZnO (0002) and ZnO (1012) double-crystal X-ray diffraction ω-scan peaks are 460″ and 1105″ respectively. The crack density of ZnO surface is only 20 cm-1 by optical microscope graph determination. Mean square root roughness is 1.5 nm from the 3 μm×3 μm atomic force microscope scanning graph. The in-situ laser reflectance trace shows that a quasi-two-dimensional growth mode is obtained and the growth rate is 4.3 μm/h. Free exciton emission and binding exciton emission accompanied by their longitudinal optical phonon replicas are observed from the photoluminescence (PL) spectrum at 10 K. All the results show that AlN buffer layer is an effective route to obtain high quality ZnO film on Si (111) substrate by MOCVD.