中文摘要：

使用自行研制的椭球谐振腔式MPCVD装置，以H2-cH4为气源，就高功率条件下cH4浓度对金刚石膜的生长速率和品质的影响规律进行了研究，并在此基础上进行了大面积光学级金刚石膜的沉积。利用扫描电镜、激光拉曼谱仪、傅里叶红外光谱仪对金刚石膜的表面和断口形貌、金刚石膜的品质、红外透过率等进行了表征。实验结果表明，使用自行设计建造的椭球谐振腔式MPCVD装置在高功率条件下通过提高cH4浓度会使金刚石膜的生长速率增加，但当CH。浓度达到一定比例后．金刚石膜的生长速率将不再继续提高。cH4浓度在0．5％～2％时制备的金刚石膜品质较高；自行设计建造的椭球谐振腔式MPCVD装置能够满足在较高功率下光学级金刚石膜的快速沉积要求．

英文摘要：

Polycrystalline diamond films were prepared by using H2-CH4 as the source gas in a newly developed ellipsoidal cavity type MPCVD reactor. The influence of CH4 concentration on the diamond growth and quality was studied in this paper. On the basis of the above research, large area optical grade free-standing diamond film was prepared. Surface and cross-sectional morphology as well as the quality of the diamond films were examined by scanning electronic microscopy and Raman spectroscopy. Furthermore, the infrared transmittance of the samples was measured by Fourier transform spectrometry. The results show that the growth rate of the diamond films increases with the increase of CH4 concentration. However, when the CH4 concentration is increased to certain level, the diamond growth rate will no longer increase. High quality diamond films can be prepared when the CH4 concentration is between 0.5%-2%. The results prove that high quality optical grade diamond films can be obtained by this newly developed ellipsoidal cavity type MPCVD reactor.