STATISTICAL APPROACH FOR OPTIMIZING SPUTTERING CONDITIONS OF HIGHLY ORIENTED ALUMINUM NITRIDE THIN-FILMS

Design of experiments and the analysis of Variance (ANOVA) are very ef ficient methods to optimize the sputtering conditions for highly c-axi s oriented aluminum nitride (AlN) thin films. The effects of the five sputtering control factors. substrate temperature, nitrogen concentrat ion, rf power, sputtering pressure and sputtering time, were simultane ously investigated by only 16 experiments. It could be proved statisti cally at the 5% level that the substrate temperature, the rf power and the sputtering pressure are significant control factors for the cryst al orientation of the films. Especially, the rf power is the most impo rtant control factor. On the other hand, the effects of the nitrogen c oncentration and the sputtering time are not statistically significant . Our results were ascertained at the 95% confidence level. The full w idth at half-maximum (FWHM) of the X-ray rocking curves of the film de posited under tile optimized sputtering conditions was 2.7 degrees (si gma=1.6 degrees). The orientation of the film was the highest of the f ilms deposited on glass substrates reported to our knowledge. (C) 1998 Elsevier Science S.A.