Macro-texture and Micro-twins in Free-standing Diamond Films
CVD自支撑金刚石薄膜中的宏观织构与微观孪晶

The techniques of orientation mapping based on electron back-scattering diffraction, scanning electron microscopy and X ray diffraction were used to investigate macro-texture, microstructure and orientation evolution of grains. The preparation atmosphere with lower purity is one of the important reasons, which induces twins in large quantity in the diamond films investigated. The impurity atoms reduce the stack fault energy in diamond, lower the obstacles to the formation of twin boundaries, and therefore accelerate the appearance of twins. Frequent twining results in the texture transformation from {100} to {122}, a weakened film texture as well as the tendency leading to isotropic properties. The {110} oriented grains keep their orientation after twinning, and therefore indicate certain orientation stability against the repeatedly twinning effects.