AlN薄膜择优取向生长机理及制备工艺

不同择优取向的AlN薄膜具有不同的物理化学性质和应用,其择优取向生长机理主要包括热力学的"能量最小化"理论和动力学的"选择进化"理论.在众多的制备方法中,通过控制工艺参数可以沉积出不同择优取向的A1N薄膜,各工艺参数对其择优取向的影响取决于沉积粒子到达衬底前携带能量的大小,它们引起的各晶面生长速率的竞争,其结果表明,择优取向晶面是该沉积条件下生长速率最快的晶面.在诸多工艺参数中,靶基距、离子束轰击是控制AlN薄膜择优取向的最重要工艺参数,靶基距增大容易得到(100)晶面择优取向的AlN薄膜,而一定范围内离子束轰击能量和轰击角度的增大会促进(002)晶面择优取向生长.

Growth Mechanism and Synthesizing Methods of Preferential Orientation of AlN Thin Films

AlN thin films with different preferential orientations have dissimilar physical and chemical properties and the underlying mechanisms that determine the preferential orientations of AlN thin films contain "energy minimization" of thermodynamics and "evolutionary selection" of kinetics.AlN thin films with different preferential orientations can be fabricated by optimizing deposition conditions among many synthesizing methods.The effects of factors on the preferential orientation may be contributed to the energy differences of the depositing particles before their reaching the substrate,which induces the competition of growth rate between different planes.The investigative results indicate that the preferential orientation plane is a plane with the highest growth rate at the deposition conditions.And among all the control factors,the target-to-substrate distance and ion beam bombardment are the most important factors of controlling preferential orientation of AlN thin films.It is also found that a longer target-to-substrate distance is conductive to the(100) plane preferential orientation and a higher ion beam energy and angle are beneficial to the(002) plane preferential orientation in some extent.