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Mapping crystalline quality in diamond films by micro-Raman spectroscopy

1998; Elsevier BV; Volume: 7; Issue: 2-5 Linguagem: Inglês

10.1016/s0925-9635(97)00262-8

1879-0062

C.D.O. Pickard, Timothy J. Davis, W.N. Wang, J. W. Steeds,

Ion-surface interactions and analysis

It is known that different growth sectors within diamond films grown by chemical vapor deposition can contain different concentrations of defects. The defects in the diamond can be in the form of inclusions of non-diamond carbon. The quality of the diamond can be observed by the change in the ratios of diamond and non-diamond components in the Raman spectrum and in the widths of the Diamond Raman Line. In (001) textured growth, the (001) sectors are observed to be made up of good quality diamond, whereas the neighboring (111) growth sectors have high concentrations of defects and inclusions. Because of the transparency of diamond, it is possible to map the Raman signal with a confocal microscope to depths of hundreds of microns. In this way, it has been possible to show that the regions of relatively defect-free diamond lie within inverted pyramids. The bases of these pyramids correspond to the observed square (001) facets, whereas the sides of the pyramid correspond to (111) planes. This feature of textured diamond films has been observed by transmission electron microscopy of cross-sections of such films, but this is the first time that it has been shown in-situ. The "Blue-Cross" of defect related luminescence [N.C. Burton, J.E. Butler, A.R. Lang, J.W. Steeds, Proc. R. Soc. Lond. A 449 (1995) 555–566] is observed by PL and correlates well with a mapping of the FWHM. The result demonstrates the ability of confocal micro-Raman spectroscopy to map the crystalline quality in diamond films on a micron scale. It is demonstrated for the first time that the pattern of defect densities previously observed by TEM can be observed in particular growth features of diamond films by confocal Raman spectroscopy.