沉积温度突变导致金刚石膜中大量黑色缺陷形成的孪晶模型

Twin Model on Dark Features Formation in Diamond Films by Deposition Temperature Changed

提出了沉积温度突变时黑色缺陷形成的孪晶机制模型。这一模型提出的基本假设为:沉积温度改变时,金刚石膜的表面上产生贯穿型的孪晶,孪晶以及原来的晶粒的各晶面均将按α2d所规定的生长速率扩张,在生长时相邻晶粒的晶界处形成了一种形如"峡谷"状的、相邻晶面夹角过小的局部环境,后者将导致活性气体扩散的过程难于进行,从而形成黑色缺陷。在此假设的基础上,利用水平集方法对此模型进行了二维的模拟,并通过实验进行了验证。模拟及实验的结果表明,在金刚石膜沉积的过程中,沉积温度的突变将通过在众多金刚石晶粒的表面诱发产生孪晶,显著提高金刚石膜中黑色缺陷的形成几率。

Dark feature is important for each performance of polycrystal diamond film. Twin mechanism on dark feature was established. The simulation basic assumption that penetration twin were formed on diamond face with deposition temperature changed and were grown with initial grains as α2d. Dark features were formed at grain boundary which it was formed such as ＂canyon＂ shape and the angle between adjacent crystal face was too small because it was difficult for gas diffusion. Twin model was simulated by Level-Set method and was confirmed by experiment. The result indicates the number of dark feature is accelerated by increased grain boundary due to formed of twins with deposition temperature changes.