Laser Spectroscopy of the Ar(1s3,5) and CH in Ar + CH4 DBD for a-C:H Deposition System

Abstract

A dielectric barrier discharge in Ar and CH 4 gas mixtures used for a-C:H film deposition was investigated. The number densities of Ar(1s 2: resonant level) and Ar(1s 3, 5 : metastable levels) atoms were measured using a high sensitive detection method based on plasma modulation and laser absorption spectroscopy. The CH(X 2 Π) radical number density was measured by an actinometry method. The excitation transfer process from the Ar(1s 5 ) atom to the CH(A 2 ∆) radical was detected by a laser collisionally induced fluorescence method. The a-C:H film properties (the content of sp 3 and sp 2 hybridization and the content of the CH 3 and CH 2 hydrocarbon groups) were correlated with the number densities of the Ar(1s 5 ) atom and the CH(X 2 Π) radical.In the a-C:H film, maximum value of the sp 3

Correlation between a-C:H film properties and Ar/CH4 dielectric barrier discharge

“…The ratio r of the CH 4 partial pressure to the total (Ar/CH 4 ) The number density of excited Ar atom on 1s 5 level (N i ), was measured using a laser absorption spectroscopy (LAS) method [8,9]. We used a Litmann cavity tunable diode laser (Sacher Lasertechnik) for the Ar transition at k 0 = 777.589 nm (1s 5 -2p 7 ).…”

“…The identification of vibrational frequencies of various C-H n stretching modes are based on the data listed in literature [1,6]. Each component was fitted with a Gaussian [1,9]. From a(x), we evaluated the content of sp 3 and sp 2 species (Fig.…”