掺杂CVD金刚石薄膜的应力分析

Study of the stress in doped CVD diamond films

在不同实验条件下,用微波等离子体化学气相沉积(MPCVD)技术在Si基体上制备了S掺杂和B-S共掺杂CVD金刚石薄膜,利用X射线衍射仪和拉曼光谱仪研究掺杂对CVD金刚石薄膜的应力影响.研究结果发现,随着S掺杂浓度的增加,薄膜中sp2杂化碳含量和缺陷增多,CVD金刚石薄膜压应力增加;小尺寸的B原子与大尺寸的S原子共掺杂时,微量B的加入改变了CVD金刚石薄膜的应力状态,共掺杂形成B-S复合体进入金刚石晶体后降低金刚石晶体的晶格畸变程度,减少S原子在晶界上偏聚数量和晶体中非金刚石结构相含量,降低由于杂质、缺陷及sp2杂化碳含量产生的晶格畸变和薄膜压应力,提高晶格完整性.

Sulphur-doped and boron-sulphur co-doped diamond thin films were prepared using chemical vapour deposition （CVD） on Si substrates under different conditions. The influence of doping on stress in CVD diamond films were investigated with X-ray diffraction and Raman spectra. The results show that the sp^2-carbon content, the concentration of defects and the residual compressive stress in CVD diamond films increase with increasing of sulphur content. Compared with sulphur doping of diamond films, the boron-sulphur co-doping with few boron atoms facilitates sulphur atom incorporation into diamond crystal. The boronsulphur complexes in diamond can reduce crystal lattice distortion and crystal imperfection. As a result, sp^2-carbon content and residual compressive stress in boron-sulphur co-doped diamond are reduced, and diamond crystal prefection is improved.