二氧化碳对同质外延生长单晶金刚石内应力的影响

本文研究了在反应气体中引入不同浓度的CO₂对微波等离子体化学气相沉积(MPCVD)法同质外延生长单晶金刚石内应力的影响，并对其作用机理进行了分析。研究发现，随着CO₂浓度增加，单晶金刚石内应力逐渐减小，这是由于添加的CO₂提供了含氧基团，可以有效刻蚀金刚石生长过程中的非金刚石碳，并能够降低金刚石中杂质的含量，从而避免晶格畸变，减少生长缺陷，并最终表现为单晶金刚石内应力的减小，其中金刚石内应力以压应力的形式呈现。此外反应气体中加入CO₂可以降低单晶金刚石的生长速率和沉积温度，且在合适的碳氢氧原子比(5∶112∶4)下能够得到杂质少、结晶度高的单晶金刚石。

Effect of Carbon Dioxide on Internal Stress of Single Crystal Diamond Grown by Homogeneous Epitaxy

In this paper, the effect of introducting different concentration CO₂ into reaction gas on the internal stress of single crystal diamond grown by microwave plasma chemical vapor deposition (MPCVD) homogeneous epitaxy was studied, and its mechanism was analyzed. Results show that with the increase of CO₂ concentration, the internal stress of single crystal diamond decreases gradually. This is because the added CO₂ provides oxygen containing groups, which can effectively etch the non-diamond carbon in the diamond growth process, and reduce the content of impurities in the diamond, so as to avoid lattice distortion and reduce growth defects. This ultimately shows the reduction of the internal stress of single crystal diamond, which is in the form of compressive stress. Besides, the addition of CO₂ in reaction gas can reduce the growth rate and deposition temperature of single crystal diamond, and single crystal diamond with less impurities and high crystallinity can be obtained at a suitable carbon hydrogen oxygen atomic ratio (5∶112∶4).