不同温度下同质外延生长单晶金刚石的应力分析

Stress Analysis of Homoepitaxial Growth of Single Crystal Diamond at Different Temperatures

本文利用微波等离子体化学气相沉积法(MPCVD)对不同温度区间下同质外延单晶金刚石的应力作出了相关研究,讨论了不同温度区间下单晶金刚石内部产生应力的原因。结果表明在低温区间(700~720℃)与高温区间(870~890℃)下生长金刚石内部均产生裂纹,总应力以本征应力为主,且以拉应力形式呈现。低温区间(700~720℃)下由于内部石墨杂质的生成使之产生过大的拉应力,而高温区间(870~890℃)下则是由于单晶金刚石生长面多晶点的出现导致拉应力集中从而产生裂纹。在合适的温度区间(770~830℃)下能同质外延生长出无裂纹高质量的单晶金刚石,总应力较小且热应力为主,以压应力形式呈现。

In this paper,the stress of single crystal diamond homoepitaxial growth by microwave plasma chemical vapor deposition（MPCVD） at different temperature has been studied. The causes of generation of stress on single crystal diamond at different temperature were investigated. The results show that the presence of crack within homoepitaxial diamond layer under the low temperature（700-720 ℃） and the high temperature（870-890 ℃） were attributed to intrinsic stress,and the total stress is presented in the form of tensile stress. The internal graphite phases led to generation of stress of single crystal diamond under the low temperature（700-720 ℃）,the polycrystalline spots of diamond surface appeared and resulted in stress concentration in the local area,which caused cracks in the single crystal diamond under the high temperature（870-890 ℃）. High-quality single crystal diamond with homoepitaxial growth without cracks was proved to be deposited in the range of 770-830 ℃. The total stress was smaller than samples prepared in other temperature ranges. The total stress is presented as compressive stress.