Diamond and Related Materials 11 (2002) 153–159 0925-9635/02/$ - see front matter  2002 Elsevier Science B.V. All rights reserved. PII: S0925-9635 Ž 01 . 00573-8 Synchrotron radiation X-ray analysis of boron-doped diamond films grown by hot-filament assisted chemical vapor deposition Leide L.G. Silva , Margareth K. Franco , Fabiano Yokaichiya , Neidenei G. Ferreira , a,d b c a Evaldo J. Corat * a, Instituto Nacional de Pesquisas Espaciais – INPE, CP 515, 12201-970, Sao Jose dos Campos, SP, Brazil a ˜ ´ Laboratorio Nacional de Luz Sincrotron – LNLS, Campinas, SP, Brazil b ´ Universidade Estadual de Campinas – UNICAMP, Campinas, SP, Brazil c Instituto Tecnologico de Aeronautica – ITA, Sao Jose dos Campos, SP, Brazil d ´ ´ ˜ ´ Received 8 February 2001; received in revised form 27 September 2001; accepted 30 September 2001 Abstract 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 B O solution in methanol. The B y C ratio in methanol varied from 2000 to 20 000 2 3 ppm and the gas flow rates were controlled so that boron incorporation to the film varied in the range from 10 to 10 boron y 18 21 cm . All other process parameters were kept unchanged to allow comparison only of the influence of the doping level. The film 3 analyses were performed at the X-ray diffraction beamline of the Laboratorio Nacional de Luz Sincrotron – LNLS, Brazil. The ´ Debye–Scherrer configuration was used in this study. A high intensity monochromatic beam at ls1.46 A was used and an ˚ excellent signal to noise ratio was obtained for 2u varying from 208 to 1508. 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=10 boron y cm .  2002 Elsevier Science B.V. All rights reserved. 19 3 Keywords: Boron-doped diamond; Synchrotron radiation; X-Ray diffraction 1. Introduction Diamond has various excellent physical and chemical properties such as high thermal conductivity, wide band gap, high electron and hole mobility, and chemical inertness w1x. With such properties and the possibility of doping to produce semiconductor diamond w2x by chemical vapor deposition, it is of great interest for potential use in high temperature electronics, harsh environment detectors and electrochemistry. Electronic applications need single crystal films, which nowadays are still considered a big challenge. Some alternative electronic components and detectors have already been * Corresponding author. Fax: q55-12-341-1869. E-mail address: corat@las.inpe.br (E.J. Corat). reported. Electrochemical applications of boron-doped diamond films have developed considerably in the last few years and are considered a very promising research area w3,4x. Boron-doped diamond electrodes present a larger potential window than any metallic or even glassy carbon electrodes. The double layer capacitance is low w5x. Its use with some metal incorporation opens a whole new area as a host material for catalysts. Studies on the effects of boron incorporation on diamond structure and lattice parameter (a) have been performed by X-ray diffraction on CVD homoepitaxial films, CVD synthetic crystals and CVD polycrystalline films. For synthetic film Voronov et al. w6x. report an increase of the lattice parameter above 1.7=10 boron 19