c轴择优取向AlN薄膜的制备研究

采用MOCVD法在蓝宝石(0001)单晶衬底上生长AlN压电薄膜。用XRD和原子力显微(AFM)技术表征薄膜的微观结构。研究了衬底温度、TMA和NH3流量、反应室气压对AlN薄膜织构特性的影响,并对薄膜生长的工艺参数进行了相应优化。结果表明:在优化条件下制备的AlN薄膜高度c轴择优取向,(0002)峰摇摆曲线半高宽仅为0.10°,且薄膜表面平整,椭圆偏振法测出其折射率为2.0～2.4。

Research on preparation of AlN thin films preferentially orientated to c-axis

AlN thin films were grown on hexagonal α-Al2O3 (0001) substrates by metalorganic chemical vapor deposition (MOCVD). The microstructure and surface morphology of the obtained films were characterized by performing X-ray diffraction (XRD) and atomic force microscopy (AFM) analysis. The effect of growth parameters on the microstructure was systematically studied and the parameters considered included the substrate temperature, the flux of TMA and NH3, and the growth pressure in the reactor. The growth condition of AlN thin films was optimized accordingly. It is found that the AlN thin films fabricated under optimized condition show a smooth surface and preferentially orientate to c-axis in a high degree, and the full width at half maximum (FWHM) of the rocking curve around (0002) diffraction peak is only 0.10°. The refractive index of these AlN thin films, measured by elliptical polarimeter, is between 2.0 and 2.4.