Raman diamond films

Raman Microspectroscopy. Raman spectra of small soflds or small regions of soflds can be obtained at a spatial resolution of about 1 p.m usiag a Raman microprobe. A widespread appHcation is ia the characterization of materials. For example, the Raman microprobe is used to measure lattice strain ia semiconductors (30) and polymers (31,32), and to identify graphitic regions ia diamond films (33). The microprobe has long been employed to identify fluid iaclusions ia minerals (34), and is iacreasiagly popular for identification of iaclusions ia glass (qv) (35). 

D.S. Knight, W.B. White, Characterization of diamond films by Raman spectroscopy, Journal of Materials Research, 4 (2011) 385-393. 

M. Mermoux, B. Marcus, L. Abello, N. Rosman and G. Lucazeau, In situ Raman monitoring of the growth of CVD diamond films, J. Raman Spectrosc., 34, 505-514 (2003). 

To evaluate the crystallinity of the films, Raman spectroscopy is used. A typical Raman spectrum is presented in Fig. 4. Of the crystalline diamond, a narrow peak at a frequency of 1332 cur1 is characteristic, which is caused by the first-order phonon scattering by the crystal lattice. The non-diamond carbon is represented in the spectrum by two diffuse bands at ca. 1350 and 1550 cm-1. When comparing the peaks height, one should keep in mind that the Raman signal is 50 times more sensitive to the non-diamond carbon than to the crystalline diamond [20], In the high-quality diamond films used as electrodes, the non-diamond carbon component rarely exceeds 1%. Raman spectroscopy data have been corroborated by the independent impedance spectroscopy measurements (see below). According to [21], the inner layer of a diamond film is enriched with the admixture of non-diamond carbon as compared to its outer layer. 

It turned out that the admixture of sp2-carbon exerts a decisive effect on the electrode quality of diamond films. And yet, modern physical and optical experimental techniques, like Raman and Auger spectroscopy, AFM, etc., failed in the elucidation of subtle effects exerted by the admixture of non-diamond carbon on the behavior of polycrystalline diamond films it is the electrochemical measurements that give plausible information [22] (see Section 6.3). 

A high-quality diamond film electrode needs high purity and quality diamond film fully covering the substrate to limit the exposure of the substrate to the environment. Micro-Raman spectroscopy, X-ray diffraction (XRD), and scanning electron... 

Fig. 3.7 Typical micro-Raman (a), XRD (b) and SEM (c) characterization results of diamond film deposited on titanium substrate...

MehtaMenon, P., Edwards, A., Feigerle, C. S., Shaw, R. W., Coffey, D. W., Heatherly, L., Clausing, R. E., Robinson, L. and Glasgow, D. C. (1999), Filament metal contamination and Raman spectra of hot filament chemical vapor deposited diamond films. Diam. Relat. Mater., 8(1) 101-109. 

Fig. 6.2 Raman spectrum of boron-doped diamond film on silicon (a) silicon, (b) boron atoms, (c) diamond (sp3 carbon), and (d) other carbon forms (amorphous)...

Ager JW, Veirs DK, Rosenblatt GM (1991) Spatially resolved Raman studies of diamond films grown by chemical vapor deposition. Phys Rev B 43(8) 6491... 

Bormett RW, Asher SA, Witowski RE, Partlow WD, Lizewski R, Pettit F (1995) Ultraviolet Raman spectroscopy characterizes chemical vapor deposition diamond film growth and oxidation. J Appl Phys 77 5916... 

In this monograph, a number of notations, units, and abbreviations will be used, and they are summarized in Appendix A. It contains lists of notations for crystal orientations, process parameters for CVD, analytical techniques, CVD reactors, crystal growth, and carbon materials in addition to a description of standard diamond film characterizations, i.e. Raman spectroscopy and cathodoluminescence (CL). The readers are recommended to just quickly read through Appendix A at this point. 

In Ref. [257], Sii- Cx alloy films with x< 0.1 were deposited on Si by molecular beam epitaxy (MBE) to use them for the substrates of heteroepitaxial diamond films. It was expected that when x = 4.33%, a perfect lattice match of Sii C c D = 2 3 occurs and the degree of orientational alignment could be improved. An EIOD film, grown to a thickness of 20 pm using the BEN process, successfully resulted in a (100)-oriented film with (100) faces at the film surface, but the FWHM of the (111) XPF was 6°, the same value as when the direct nucleation of diamond was done on Si using BEN. The results of Raman spectroscopy and XRD of the diamond films were not dependent on the x value. It was thus confirmed that the orientational characteristics of the HOD films had no significant dependence on the C content of the Sii C,v layers. This work can be compared with that of Ref. [258], where layers with x= 1.4 and 3.5% were deposited on Si(lOO) by... 

Polarized Raman spectroscopy of HOD films was also studied in Refs. [228, 351, 352]. The HOD film was grown by the three-step process under conditions listed in Table H.3 [351]. The angular dependence of polarized Raman spectroscopy was measured for both the 1332-cm line of the diamond film of 40-pm thickness and the 515-cm line of the Si(lOO) substrate. The results are shown in Figure 11.43. 

For a 47-pm thick free-standing diamond film, the Raman peak shifted from the interface to the growth surface, as shown in Figure 11.47. 

The internal stress within the diamond film grown on Pt(lll) substrate was characterized by confocal Raman spectroscopy [401, 402]. The film thickness was... 

FIG. 2(a) Scanning electron micrograph of a continuous diamond film grown on C-ji, thin film on a Si substrate, (b) Raman spectra of diamond film of Fig. 2(a). 

Raman spectroscopy gave structural characterisation of nanocrystalline diamond films formed by pulsed laser deposition in an oxygen atmosphere.300 Raman and IR spectra were used to follow diamond deposition on mirror-polished Si single crystal substrates.301 Nanocrystalline diamond spheres were also characterised by Raman spectroscopy.302... 

FIGURE 5.4 SEM image and Raman spectrum of diamond film obtained by the combustion flame method t= 1.05. 

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