化学气相沉积金刚石微球的生长机制研究

Chemical vapor deposition of diamond microsphere:Investigation of growth dynamics

采用微波等离子体化学气相沉积法,在过饱和碳离子浓度条件下,在单晶硅衬底上制备了球形结构的多晶金刚石微球,通过控制沉积气压与温度的变化,研究了金刚石由石墨生长区向纳米晶的球形结构、再到具有良好结晶性的金刚石生长区的过渡过程。结果表明:沉积气压与温度的升高导致微球的粒径增大,微球由sp^3、sp^2键共存相转变为较纯的金刚石相;在一定的碳离子过饱和度和气压、温度范围内,微球的形成主要受二次形核过程的控制。气压和温度升高后,微球呈<110>取向生长,微球的形成主要受(111)面高密度孪晶和层错缺陷的控制,揭示了化学气相沉积金刚石不同生长区内二次形核机制与孪晶层错机制诱导的金刚石微球的生长过程。

The spherical polycrystalline diamond microspheres were prepared on the monocrystalline silicon substrate by microwave plasma chemical vapor deposition. By changing the deposition pressure and temperature, the transition of diamond from graphite growth region to nanocrystalline spherical structure, and to diamond growth region with good crystallization was studied. The particle size increases with the pressure and temperature increasing, and microspheres change from sp 3 and sp 2 coexisting phase to pure diamond phase. The formation of microspheres is mainly controlled by the secondary nucleation mechanism within a certain degree of carbon oversaturation, pressure and temperature. The microsphere grows in the orientation of 〈110〉 with the pressure and temperature increasing. The formation of diamond microspheres is controlled by （111） face defects with high density twins and stacking faults, which reveals the growth process of diamond microspheres induced by secondary nucleation mechanism and twin stacking fault mechanism in different growth regions of CVD diamond.