MPCVD法合成单晶体金刚石的工艺探索(下)

Experiment of synthesizing single-crystal diamond by MPCVD

在CVD法合成单晶体金刚石技术中,如何提高生长速率、生长质量以及单晶体体积是业界关注的焦点。文章选取5粒(100)方向的合成单晶金刚石作为种晶材料,其中包含2粒IIa型CVD法合成的种晶,3粒Ib型HPHT法合成的种晶,采用MPCVD法合成单晶体金刚石,获得了较理想的阶段性进展。实验参数范围是:温度为800℃～1100℃,压力为8000～11000Pa,功率为2500W。通过显微放大观察发现样品实现三维的生长模式,即在生长过程中表面积不断扩大,厚度不断增长,并在各表面留下了有明显特征的阶梯状生长纹和锥形生长丘。其中厚度最大增值为0.52mm,重量增加0.13ct。实验中首次得到了高质量透明的金刚石生长层。拉曼光谱分析表明,合成样品均存在金刚石特征的1332cm-1强峰,部分样品还伴随有少量的非金刚石相。

In the technology of CVD synthetic single-crystal diamond, the problems of how to improve the growth rate, layer quality and single-crystal volume have become the hot spot in this field. In our experiment, the single-crystal diamonds are grown by the MPCVD method,and we have got a satisfying step progress. Five pieces of （ 100）-oriented synthetic diamonds are chosen as substrates for this experiment. Two of them are identified as type IIa, and the other three are tested as type lb. The growth temperature is approximately 800-1100℃, and the pressure is about 8-11kPa. The microwave power is stabilized 2.5kW. The surface morphologies of samples are observed and analyzed by microscope and Raman system, which show the three-dimensional growth model, step-bunched surface, and pyramidal hillocks. The most excited one increased 0.52mm and 0.13ct. We have also got transparent growth layer of high quality for the first time during this experiment. The Raman spectra shows obvious diamond peak 1332cm-1 , and in addition, some of the samples are coupled with few non-diamond phases.