Bulk and surface thermal stability of ultra nanocrystalline diamond films with 10–30 nm grain size prepared by chemical vapor deposition
Bulk and surface thermal stability of ultra nanocrystalline diamond films with 10–30 nm grain size prepared by chemical vapor deposition
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DOI：
10.1063/1.3359714
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发表时间：
2010-05
影响因子：
3.2
通讯作者：
S. Michaelson;A. Stacey;J. Orwa;A. Cimmino;S. Prawer;B. Cowie;O. Williams;D. Gruen;A. Hoffman-A.-Hof
中科院分区：
文献类型：
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作者：
S. Michaelson;A. Stacey;J. Orwa;A. Cimmino;S. Prawer;B. Cowie;O. Williams;D. Gruen;A. Hoffman-A.-Hof
研究了微波增强化学气相沉积法在硅衬底上沉积的晶粒尺寸为10-30 nm的纳米金刚石薄膜在1200 °C退火温度下的热稳定性。用近边X射线吸收精细结构（NEXAFS）谱在部分电子产额模式下记录的表面上原子层的热稳定性进行了研究。该技术表明，在靠近表面的区域内，薄膜发生了大量的热致石墨化。而在膜的本体区域中，即使在退火至1200 °C之后，也没有观察到石墨化，其中拉曼光谱或NEXAFS光谱以总电子产额模式记录。拉曼光谱确实检测到在1000 °C下退火后反式聚乙炔（t-PA）样ν1和ν3模式完全消失。二次离子质谱法，适用于调查这种相对减少氢原子浓度检测到只有约30%的氢原子的体积含量减少。这种增强的稳定性sp3杂化原子在相对于石墨化的散装区域内的碳键重排由于t-PA样片段的热分解方面进行了讨论。
The thermal stability of nanocrystalline diamond films with 10–30 nm grain size deposited by microwave enhanced chemical vapor deposition on silicon substrate was investigated as a function of annealing temperature up to 1200 °C. The thermal stability of the surface-upper atomic layers was studied with near edge x-ray absorption fine structure (NEXAFS) spectroscopy recorded in the partial electron yield mode. This technique indicated substantial thermally induced graphitization of the film within a close proximity to the surface. While in the bulk region of the film no graphitization was observed with either Raman spectroscopy or NEXAFS spectroscopy recorded in total electron yield mode, even after annealing to 1200 °C. Raman spectroscopy did detect the complete disappearance of transpolyacetylene (t-PA)-like ν1 and ν3 modes following annealing at 1000 °C. Secondary ion mass spectroscopy, applied to investigate this relative decrease in hydrogen atom concentration detected only a ∼ 30% decrease in the bulk content of hydrogen atoms. This enhanced stability of sp3 hybridized atoms within the bulk region with respect to graphitization is discussed in terms of carbon bond rearrangement due to the thermal decomposition of t-PA-like fragments.