Miranda C R B, Azevedo A F, Baldan M R, Beloto A F, Ferreira N G
Instituto Nacional de Pesquisas Espaciais/Laboratório Associado de Sensores e Materiais- INPE/LAS, Avenida dos Astronautas 1758, Jardim da Granja, São José dos Campos-SPF Caixa Postal 515, CEP 122245-970, Brazil.
J Nanosci Nanotechnol. 2009 Jun;9(6):3877-82. doi: 10.1166/jnn.2009.ns83.
Nanocrystalline diamond (NCD) films were formed on porous silicon (PS) substrate by Chemical Vapor Deposition/Infiltration (CVD/CVI) process using a hot filament reactor. This innovative procedure is determinant to grow a controlled three-dimensional diamond structure with diamond grains formation in the pores, covering uniformly the different growth planes. In this CVI process, a piece of reticulated vitreous carbon (RVC) was used, under de PS substrate, as an additional solid source of hydrocarbon that ensures the production of pertinent carbon growth species directly on PS and into its pores. PS substrates were obtained by anodization etching process of n-type silicon wafer in a hydrofluoric acid (HF) solution containing acetonitrile (CH3CN) which result in an uniform and well controlled porous distribution and size when compared with the usual ethanol solution. Depositions were performed using Ar-H2-CH4 where the methane concentration varied from 0 up to 1.0 vol%, to analyze the influence of RVC use as an additional carbon source on growth mechanism. Scanning Electron Microscopy (SEM) and Field Emission Gun (FEG) were used to investigate PS and NCD film morphology. SEM images of NCD showed faceted nanograins with average size from 5 to 16 nm and uniform surface texture covering all the supports among the pores resulting in an apparent micro honeycomb structure. Raman spectra confirmed the existence of sp2-bonded carbon at the grain boundaries. The spectra showed a peak that may be deconvoluted in two components at 1332 cm(-1) (diamond) and 1345 cm(-1) (D band). Two shoulders at 1150 and 1490 cm(-1) also appear and are assigned to transpolyacetylene (TPA) segments at the grain boundaries of NCD surfaces. In addition, X-ray diffraction analyses of all films presented characteristic diamond diffraction peaks corresponding to (111), (220) and (311).
采用热丝反应器通过化学气相沉积/渗透（CVD/CVI）工艺在多孔硅（PS）衬底上形成了纳米晶金刚石（NCD）薄膜。这一创新工艺对于生长具有可控三维金刚石结构至关重要，该结构在孔隙中形成金刚石晶粒，均匀覆盖不同的生长平面。在这个CVI工艺中，在PS衬底下方使用了一块网状玻璃碳（RVC）作为额外的烃类固体源，以确保在PS及其孔隙中直接产生相关的碳生长物种。PS衬底是通过在含有乙腈（CH3CN）的氢氟酸（HF）溶液中对n型硅片进行阳极氧化蚀刻工艺获得的，与通常的乙醇溶液相比，该工艺能产生均匀且可控的孔隙分布和尺寸。沉积过程使用Ar - H2 - CH4，其中甲烷浓度从0变化到1.0 vol%，以分析使用RVC作为额外碳源对生长机制的影响。使用扫描电子显微镜（SEM）和场发射枪（FEG）来研究PS和NCD薄膜的形态。NCD的SEM图像显示出多面纳米晶粒，平均尺寸为5至16纳米，表面纹理均匀，覆盖了孔隙间的所有支撑物，形成了明显的微蜂窝结构。拉曼光谱证实了在晶界处存在sp2键合的碳。光谱显示在1332 cm(-1)（金刚石）和1345 cm(-1)（D带）处有一个可解卷积为两个成分的峰。在1150和1490 cm(-1)处还出现了两个肩峰，它们被归因于NCD表面晶界处的反式聚乙炔（TPA）段。此外，所有薄膜的X射线衍射分析都呈现出对应于（111）、（220）和（311）的特征金刚石衍射峰。
