- 學位論文
HFCVD 含硼鑽石輔助偏壓沉積之研究
Deposition of Boron-doped Diamond Films by Bias-Assisted HFCVD
摘要
本研究在於探討熱燈絲氣相化學沉積（HFCVD）鑽石的過程中摻雜硼原子並 增加輔助負偏壓電場，對鑽石沉積速率的影響。藉由電子顯微鏡（Scanning Electron Microscopy）、X-ray 繞射（X-Ray Diffraction）、拉曼光譜等分析方法，對鑽石薄 膜之表面形貌、結晶構造、薄膜品質、與表面型態作一分析。結果顯示，硼加入 反應氣體後會降低鑽石的成核速率，晶界因此減少。較高的成核速率會導致低品 質的鑽石薄膜，因為雜質容易存在於晶界。拉曼光譜指出硼的加入會提昇鑽石薄 膜的品質，鑽石(111)面的X-ray 強度在B/C 1000ppm 會達到最高值，顯示出硼可 以幫助(111)面的成長。在鑽石沉積過程中摻雜硼原子並輔助一負偏壓電場有助於 提升鑽石的沉積速率。在CH4/H2 為2.3％、反應氣體總流量100sccm、反應壓力約 20torr、基板溫度約850℃、鎢絲溫度約2100℃、含硼量1000ppm、偏壓電流維持 約6mA 的條件下，鑽石沉積速率可提升到1.5£m/hr，較原先未加輔助偏壓狀況下， 鑽石沉積速率提升約2 倍。
並列摘要
This research is to investigate the influence of doped boron atoms and the assisted negative bias on the deposition rate of diamond films by hot filament chemical vapor deposition (HFCVD). The surface morphology, crystallinity, and quality of diamond thin films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy. It was shown that the nucleation rate of diamonds was suppressed by taking advantage of boron-content precursor gas. Higher nucleation rate reduced the quality of diamond films because impurities appeared easily on the grain boundary. According to Raman spectra, the diamond film was of improved quality due to the incorporation of boron atoms. The XRD intensity of (111) surface reached the maximum at a boron content (B/C) of 1000 ppm. The positive effect of doped boron atoms on the growth of (111) surface was thus confirmed. The deposition rate of diamond films increased if boron atoms were doped and one negative bias was applied during the deposition process. A mixture of 2.3% CH4 in hydrogen was used at a total flow rate of 100 sccm and a pressure of 20 torr. The temperature of the substrate and tungsten filaments was maintained at 850℃ and 2100℃, respectively. Under the boron content of 1000 ppm and the biasing current of 6 mA, the deposition rate could increase to 1.5 μm/hr, which was about twice larger than that formed without bias.