织构对CVD自支撑金刚石薄膜残余应变的影响

Influence of texture on residual strain in CVD free standing diamond films

计算了薄膜试样不同方向的弹性模量,研究了织构和甲烷浓度对CVD自支撑金刚石薄膜的宏观残余应变的影响．结果表明,织构使CVD金刚石薄膜的弹性模量和宏观残余应变呈现各向异性．甲烷浓度的升高导致织构组分密度水平变化,使薄膜的弹性模量增大,从而降低残余应变;另一方面,杂质浓度的升高增大宏观残余应变．改变薄膜沉积工艺参数可调整织构,从而调节薄膜的残余应力．

The texture, macro-residual strain and graphite content in CVD free standing diamond films were investigated by X ray diffraction. The Young＇ s modulus in different directions of the films were calculated based on phenomenological theory and orientation distribution function （ODF）. Results show that the Young＇s modulus and the residual strain in CVD diamond films are anisotropic because of texture. The increase of methane concentration induces the variation of texture component density, which increases the Young＇s modulus, so the residual strain decreases; on the other hand, the increase of impurity content enhances the residual strain in the films, but the effect of texture is dominating. The texture in CVD diamond films could be adjusted by adjusting fabrication parameters of diamond films, so the residual stress can be regulated.