摘要
以P型(100)取向的单晶硅片为衬底,采用微波等离子体化学气相沉积(MPCVD)法,通过在反应气源中添加不同比例的CO2制备光学级金刚石膜。通过Raman光谱、X射线衍射(XRD)和扫描电子显微镜(SEM)表征金刚石膜的结晶质量、晶粒取向和表面形貌。结果表明:增加反应气源中CO2/CH4流量比,在不改变金刚石膜物相纯度的情况下,有利于提高金刚石薄膜的结晶质量;适量的CO2/CH4流量比有利于获得晶粒形貌规则、完整且尺寸均匀的高[111]取向的金刚石膜。傅里叶变换红外光谱(FT-IR)(红外光透过率)测试发现晶界密度小、晶粒尺寸均匀、形貌规则且表面平整的自支撑金刚石膜具有更高的红外(IR)透过率,表明在反应气源中适量地引入CO2有利于提高金刚石膜的光学性能,这可能与CO2引入后产生的含氧基团能抑制非金刚石相,促进取向金刚石相的生长有关;在微波功率6 k W、气压13 k Pa、基片温度850℃、CH4流量为15 ml·min-1(标准状况)的条件下,CO2/CH4流量比为0.45时可制备出具有高质量和高红外透过率的金刚石光学膜。
Microwave plasma chemical vapor deposition （MPCVD） method was employed to deposit optical diamond fihns on P-type （100） oriented single crystal silicon wafer substrates, in which flow of CO2 gas with different ratios was introduced into the reaction gas source. The crystallinity, grain orientation and surface morphology of as-deposited optical diamond films were systematically character- ized by Raman spectroscopy, X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The results suggested that the in- crease of the flow ratio of CO2 to CH4 in the reaction gas source contributed to the improvement of erystallinity without changing the pu- rity of optical diamond films. Optical diamond films with high [ 111 ] preferred orientation and regular grains as well as uniform grain size were obtained by optimizing the flow ratio of CO2 to CH4. Fourier transform infrared spectroscopy （FT-IR） measurements revealed that the free-standing optical diamond films with low density of grain boundaries, uniform grain size, regular and flat surface morpholo- gy had higher infrared （IR） transmittance, indicating that the introduction of suitable CO2 amounts contributed to the improvement of optical properties of diamond films. The results could be related to the existence of various oxygen-containing groups from the excitation of CO2 gas that could promote the growth of oriented diamond phase and inhibited the non-diamond impurity phase. Finally, the optimal conditions for preparing optical diamond films with high quality and high infrared （IR） transmittance were as follows： the CO2 to CH4 ratio of 0.45, the CH4 flow rate of 15 ml·min-1 （ standard condition）, the microwave power of 6 kW, the gas pressure of 13 kPa, and the substrate temperature of 850 ℃.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2015年第5期428-434,共7页
Chinese Journal of Rare Metals
基金
国家自然科学基金委员会与中国工程物理研究院联合基金项目(U1330127)
国家自然科学基金青年基金项目(11205127)
碳纳米材料四川省青年科技创新研究团队专项(2011JTD0017)资助
