约束式热丝CVD法制备金刚石的研究

为提高热丝CVD法沉积金刚石薄膜的生长速率，以丙酮和氢气作为反应气源，利用自制的半封闭式空间约束装置，将热丝、衬底、反应气体聚集在狭小空间内，研究不同气体流速条件下的金刚石薄膜沉积情况；使用SEM和Raman光谱表征所合成的薄膜。结果表明:采用约束式沉积法可以显著提高沉积速率，本实验在230 cm3/min（标况）气体流速下获得最大沉积速率6.31 μm/h，比未约束时增大了近一倍。随着气体流速增大，沉积速率先增大后减小；气体流速86~115 cm3/min（标况）时，晶粒尺寸为微米级；气体流速115~575 cm3/min（标况）时，晶粒尺寸减小至纳米级。Raman光谱检测显示:约束式沉积所得薄膜总体质量较好，但随气体流速增大而逐渐降低。 

Study on diamond film growth by hot filament CVD in confined space

In order to increase the growth rate of diamond film deposition by hot filament CVD, the filament, the substrate and the gas were limited in a narrow space with a self-made semi-enclosed space restraint device. Acetone and hydrogen were used as the reaction gas source. The deposited diamond films under different gas flow rates were characterized by SEM and Raman spectroscopy. Results showed that the deposition rate could be significantly improved by restraint device. In this experiment, the maximum deposition rate of 6.31 μm/h was obtained at a gas flow rate of 230 sccm, which was nearly two times that of the unconstrained method. As gas flow rate increased, the deposition rate increased first and then decreased. The grain size was micron level at gas flow 86 to 115 sccm, while it changed to nano size at gas flow 115 to 575 sccm. The Raman spectroscopy showed that the quality of the constrained deposited film was generally better, and gradually decreased with the increase of gas flow rate.