Experimental design method applied to microwave plasma enhanced chemical vapor deposition diamond films

The Taguchi method with an L18 orthogonal array design has been used in thi s study to investigate the effect of various control factors on the perform ance of microwave plasma enhanced chemical vapor deposition diamond films. The full-width at half-maximum (FWHM) of Raman peak was used as the respons e item in the design. Raman spectroscopy is one of the most common techniqu es of diamond film characterization, and in general, the (111) diamond with better crystallinity exhibits a smaller FWHM of the Raman peak (1332 cm(-1 )). As the result of Taguchi analysis in this study, the bias voltage, the methane concentration and the hydrogen flow rate are the most influencing f actors on the CVD diamond quality. The optimal parameters were also obtaine d from the Taguchi method. The FWHM in the confirmation experiment is 4.5 c m(-1), while the original 18 runs demonstrate linewidths between 4.7 and 11 .6 cm(-1). (C) 2001 Elsevier Science B.V. All rights reserved.