直流等离子体法中脱膜开裂的金刚石膜组织结构分析

Structural Analysis of Cracked Diamond Films Grown by DC Plasma Jet during Detachment

为了解决用直流等离子体喷射法制备金刚石膜在脱膜过程中膜体开裂的问题,本文对3组脱膜开裂的金刚石膜组织结构进行了分析,发现由热应力作用产生的裂纹形貌随沉积温度的不同而呈现网状、河流状和环状,裂纹尖端的膜体具有最小的Raman谱峰半高宽值。在所研究的温度范围内,膜体断口都是穿晶断裂和沿晶断裂的混合断口,而且断口面中的占优晶面都是[111]晶面。X射线和Raman谱结果还表明沉积温度愈高,膜体中的残余应力愈大。

3 groups of remained CVD free-standing diamond films were studied in order to overcome the problem of film cracking during detachment. The crack patterns are found as net, river and circle shape, depending on the film growth temperature. The cracked section of films is the combination of transgranular and intergranular section in the whole growth temperature range. The X-ray diffraction results show that {111 } crystalline surface is the dominant surface in the cracked section, independing on the growth temperature. Raman spectra results indicate that the full width at half maximum possesses the smallest value at the tip of crack. Both X-ray diffraction results and Raman spectra results show that the residual stress in the film body increases with the increase of growth temperature.