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阐述了模板的动力学控制作用对大尺度有序结构特别是亚稳相的生长,对自由能相差很小的异构体的选择生长所具有的重要作用.汲取现有金刚石生长理论的合理思想,以模板概念为基础给出了对化学气相沉积(CVD)过程的动力学热力学综合描述1)碳原子在碳氢化合物中的化学势高于固相碳,气相碳氢化合物的碳原子有可能落到化学势较低的固态碳的各种异构体.2)气相碳通过表面反应实现向固相碳的转化.3)表面的模板作用是控制气相碳原子转换方式的主要动力学因素,不同的表面(石墨各种取向的表面及金刚石不同取向的表面)选择了落入其上的碳原子的结构方式及能量状态.4)因此,衬底的不同区域可发生几种不同的独立的表面反应过程,这些反应对应于不同表面的生长.5)而这些表面反应的方向性及速度受表面临域热力学因素的影响,反应的方向性决定了某种晶面是生长或刻蚀,在特定的温度、压强及各种气体分压下可以实现金刚石的生长和石墨的刻蚀.6)衬底局域晶格结构及键价结构和衬底表面气相的温度、压强及各种气体分压等热力学条件共同决定了成核的临界条件.7)与外界有能量和物质交换的等离子体系统,以及气相中发生的一系列化学反应,仅起到了维持某种固相表面生长所需要的非平衡热力学条件和化学条件的作用.金刚石和石墨表面具有的模板动力学控制作用,在特定热力学条件下主导自身外延层的生长方式;异质衬底的某些局域微观结构可以作为新相生长成核的局域模板;不同材料、不同的处理方法、及不同的化学环境下的衬底具有不同的局域微观结构,从而决定了多晶薄膜的取向优势.
The effect of template kinetic control on the growth of large-scale ordered structures, especially metastable phases, plays an important role in the selective growth of isomers with little difference in free energy.According to the reasonable thinking of existing diamond growth theory Based on the template concept, a kinetic thermodynamic synthesis of the chemical vapor deposition (CVD) process is given. 1) The chemical potential of carbon atoms in hydrocarbons is higher than that of carbon in solid-phase carbon and gaseous-phase hydrocarbons Fall to all kinds of isomers of solid carbon with lower chemical potential.2) The transformation of gas phase carbon into solid carbon by surface reaction.3) The template action of surface is the main kinetic factor controlling the conversion of gas carbon atoms, Different surfaces (surfaces of various orientations of graphite and surfaces of different orientations of diamond) have chosen the structure and energy state of the carbon atoms falling on them.) Thus, different regions of the substrate can undergo several different independent Surface reaction process, these reactions correspond to the growth of different surfaces.5) The direction and speed of these surface reactions are affected by the thermodynamics of the surface field, the direction of the reaction determines a certain crystal face Growth or etching, the growth of diamond and the etching of graphite can be realized under specific temperature, pressure and various gas partial pressures.6) The local lattice structure and bond structure of the substrate and the gas phase temperature on the substrate surface, Pressure and various gas pressure and other thermodynamic conditions determine the critical conditions of nucleation .7) With the outside world have energy and material exchange of plasma systems, and the gas phase of a series of chemical reactions, only played to maintain a solid The non-equilibrium thermodynamic and chemical conditions needed for phase surface growth The role of template dynamics in diamond and graphite surfaces dominates the growth mode of their own epitaxial layers under certain thermodynamic conditions. Some localized areas of heterogeneous substrates The microstructure can be used as a local template for nucleation of new phase growth. Different materials, different treatment methods and different local micro-structures of the substrate in different chemical environments determine the orientation advantages of polycrystalline thin films.