Synchrotron radiation X-ray analysis of boron-doped diamond films grown by hot-filament assisted chemical vapor deposition

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• 作者：Silva ; Leide L.G. ; Franco ; Margareth K. ; Yokaichiya ; Fabiano ; Ferreira ; Neidenei G. ; Corat ; Evaldo J.
• 关键词：Boron-doped diamond ; Synchrotron radiation ; X-Ray diffraction
• 刊名：Diamond and Related Materials
• 出版年：2002
• 期刊代码：30_09259635
• 类别：ms
• 出版时间：February, 2002
• 卷：11
• 期：2
• 页码：153-159
• 文件大小：155 K

摘要

This paper presents a synchrotron X-ray radiation analysis of boron-doped diamond films grown by hot-filament assisted chemical vapor deposition (HFCVD). The diamond films were grown at different doping levels with the introduction of boron to the gas mixture by bubbling hydrogen in a B₂O₃ solution in methanol. The B/C ratio in methanol varied from 2000 to 20000 ppm and the gas flow rates were controlled so that boron incorporation to the film varied in the range from 10¹⁸ to 10²¹ boron/cm³. All other process parameters were kept unchanged to allow comparison only of the influence of the doping level. The film analyses were performed at the X-ray diffraction beamline of the Laboratório Nacional de Luz Sincrotron – LNLS, Brazil. The Debye–Scherrer configuration was used in this study. A high intensity monochromatic beam at λ=1.46 Å was used and an excellent signal to noise ratio was obtained for 2θ varying from 20° to 150°. The difractogram for the undoped diamond film show intense peaks from the (111), (220), (311), (400) and (331) crystallographic planes. For the boron-doped films a set of new diffraction lines appear and their intensities increase considerably with the doping level. The set of diffraction peaks of similar intensities are related to a hexagonal structure and were assigned with high confidence to tungsten carbide. This reveals that the boron-doping process in HFCVD facilitates the incorporation of tungsten carbide from the filament in the diamond film. The FWHM analysis of the diamond diffraction peaks shows a dependence of film crystallinity with doping level with a definite maximum at approximately 2.3×10¹⁹ boron/cm³.