HIGH-RESOLUTION AUGER-ELECTRON SPECTROSCOPY STUDIES ON (100) AND (111) FACETS OF CHEMICAL-VAPOR-DEPOSITED DIAMOND

Diamond thin films were grown by microwave plasma and hot filament che mical vapor deposition (MPCVD and HFCVD, respectively) techniques. Fil ms were systematically characterized by x-ray diffraction, micro-Raman spectroscopy, scanning electron microscopy (SEM), and Auger electron spectroscopy (AES). Although the results obtained using various charac terization techniques are broadly similar, there are however subtle di fferences. For instance, Raman spectra show a sharp peak at similar or equal to 1332 cm(-1) corresponding to natural diamond in bath types o f films. The intensity and the position of the non-diamond band in the two sets of films differ. While the maxima of the non-diamond band in HFCVD film lies at 1450 cm(-1), in MPCVD film it occurs at 1525 cm(-1 ) Also the values of FWHM in HFCVD film (similar or equal to 7.5 cm(-1 )) are smaller than the MPCVD films (similar or equal to 9.5 cm(-1)). This may indicate that the concentration of non-diamond carbon impurit ies on the grain boundaries of HFCVD films are really small. SEM resul ts on the other hand indicate that the grain size of the MPCVD films i s larger than HFCVD films. AES was performed in a survey scan (beam si ze similar to 10 mu m X 8 mu m) and high resolution (beam size similar or equal to 0.2 mu m) mode with an initial aim to investigate the sur face characteristics and environment of carbon atoms of the diamond fi lms. In the survey scan, the spectra show a line shape typical of CVD diamond films. Anomalous results were obtained when the AES was perfor med on (100) and (111) facets in high resolution mode. This may be exp lained in terms of the surface reconstruction taking place due to hydr ogen desorption via core-hole Auger decay process. Auger depth profile s were also obtained on the facets which reveal that Si, O, and N are the dominant impurities. The impurity content of HFCVD films is observ ed to be lower by a factor of 2 as compared to MPCVD films. (C) 1998 A merican Vacuum Society.