CVD合成钻石的红外拉曼光谱分析

Analysis of CVD Synthetic Diamond by FTIR and Raman Spectrometry

用11颗高温高压合成钻石种晶在不同CH4/H2比例、温度和压强下进行CVD生长实验。对生长后样品进行了红外光谱定量分析、拉曼光谱分析及表面微形貌观察。结果表明,合成的CVD钻石有一定的内应力,晶体质量与高温高压种晶质量相似。过高的CH4/H2比例对CVD钻石的生长无明显促进作用,会增加C-H缺陷,抑制钻石的快速生长。同时,温度对CVD钻石的生长速度和生长模式起着重要的作用,适当提高合成温度有助于钻石生长台阶的形成以及生长速率的提高。

Eleven grains of HPHT synthetic diamond were used to grow CVD diamond layers under different CH4/H2 ratios, temperatures and pressures. Samples were analyzed by infrared spectroscopy(FTIR) quantitatively as well as with Raman spectrometry. The morphology of samples was also observed with Raman spectroscopy. Test results showed the crystalline quality of CVD synthetic diamond is as good as that of the HPHT synthetic diamond but with the existence of some internal stress from synthesis. The high CH4/H2 ratio has no significant effect on promoting diamond growth, but may increase C-H defects and inhibit the rapid growth rate. Furthermore, temperature plays an important role in CVD diamond growth rate. Moderate temperature increases can promote the formation of growth steps and noticeably improve the rate of growth.