Ion-Induced Processes in the Dissociative Excitation Reaction of BrCN to Synthesize Mechanically Hard Amorphous Carbon Nitride Films in the Microwave Plasma Chemical Vapor Deposition System

Abstract

High-resolution emission spectra have been observed for the dissociative excitation reaction of BrCN with the microwave-discharge flow of Ar to synthesize mechanically hard a-CNx films. From the analysis of intensity of the CN(B2Σ+–X2Σ+) emission under the conditions of trapping charged species and the addition of SF6, BrCN is found to be excited via the charge transfer from Ar+ followed by the recombination of BrCN+ with thermal electrons as well as the energy transfer from Ar(3P0,2). The relative intensity of the resonance lines of Ar+ and Ar, IAr+ /IAr, has been measured under the RF-biased condition. The dependence of IAr+ /IAr on the RF-bias voltage is found to be strongly correlated with that of the reported hardness of films [Tanaka et al.: Jpn. J. Appl. Phys. 39 (2000) 4148], confirming the proposed mechanism of film hardening by the bombardment of the film surface by Ar+.