Role of ion bombardment in forming CNx and CNxHy films deposited by r.f.-magnetron reactive sputtering and ECR plasma-activated CVD methods

Abstract

Abstract CN x and CN x H y films were deposited by r.f.-reactive magnetron sputtering and ECR PACVD, respectively. Film composition (N/C ratio) and growth rate ( V g ) were investigated, depending on the type (d.c. or r.f.) and level of substrate bias in the range 0 to −200 V. It was shown that ion bombardment influences the composition and growth rate of carbon nitride films appreciably during their deposition. An increase in r.f.-bias voltage up to −200 V results in a decrease in V g up to zero, whereas the dependence of N/C on r.f.-bias value reveals a peak at about −130 to −150 V. R.f. bias of the substrate influences the composition and growth rate of CN x and CN x H y films much more effectively than d.c. bias. The analysis of Raman spectra for both film types indicates a decrease in size of the film-forming clusters and a simultaneous arrangement of atoms towards the graphite structure with increasing ion bombardment intensity. From the resemblance of V g , N/C and Raman spectra behavior with the variation in ion bombardment characteristics, it can be concluded that the ion bombardment effect reveals common features for two essentially different deposition methods, whereas the film growth mechanisms are strongly different for these deposition techniques and substantially influence the composition and growth rate of the films.