压力对热丝化学气相沉积的CH_4/H_2/Ar气氛中的纳米金刚石薄膜生长的影响(英文)

Effect of pressure on nanocrystalline diamond films deposition by hot filament CVD technique from CH_4/H_2/Ar gas mixture

在热丝化学气相沉积体系中,系统研究了气压对CH4/H2/Ar气氛中纳米金刚石薄膜生长的影响。研究发现,体系气压对纳米金刚石的生长有很大的影响。在40 torr的气压下,在CH4/H2/Ar气氛中的Ar气含量需高达90%才能保证纳米金刚石薄膜的生长,但降低气压至5 torr时,50%的Ar气含量即可保证纳米金刚石薄膜的生长。压力对薄膜生长表面的气体浓度的影响是这个转变的主要原因。在同样的Ar含量下,在5 torr下的C2活性基团的浓度高于40 torr的浓度,因而低的Ar含量会保证纳米金刚石薄膜的生长。

The effect of pressure on the deposition of nanocrystalline diamond （NCD） films in a hot filament chemical vapor deposition （HFCVD） system was investigated using CH4/H2/Ar gas mixture. The reactor pressure was found to have the strongest influence on nucleation of nanocrystalline diamond films. The range of Ar concentration in the CH4/H2/Ar mixture that permits the deposition of nanocrystalline diamond （NCD） film at 40 torr is 90%, while the Ar concentration needed for the transition into nanocrystalline diamond phase is 50% at 5 torr. Such pressure dependence of the nanocrystalline diamond film growth was suggested to result from two competing effects of pressure on the concentration of reactive species near the film growth surface, and the C2 density at lower pressure （5 torr） is higher than that at high pressure （40 torr） at the same Ar concentration.