AVS 52nd International Symposium
    Plasma Science and Technology Friday Sessions
       Session PS-FrM

Paper PS-FrM4
Comparison of Surface Reactivity of CN, NH, and NH@sub 2@ Radicals during Deposition of Amorphous Carbon Nitride Films from r.f. Inductively Coupled Plasmas

Friday, November 4, 2005, 9:20 am, Room 302

Session: Plasma Surface Interactions III
Presenter: D. Liu, Colorado State University
Authors: D. Liu, Colorado State University
I.T. Martin, Colorado State University
J. Zhou, Colorado State University
E.R. Fisher, Colorado State University
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Carbon nitride films have received much attention because it has been proposed that the bulk modulus of @beta@-C @sub 3@N @sub 4@ may be greater than that of diamond. A number of groups have subsequently attempted to deposit carbon nitride films using various plasma techniques. However, the film deposition processes and their relationships with film properties are less studied. Here, the interactions of CN, NH, and NH @sub 2@ radicals with the carbon nitride film surface during r.f. inductively coupled plasma deposition were compared using the imaging of radicals interacting surface (IRIS) technique. Surface scattering coefficients, S, were obtained for various gas compositions of N @sub 2@+CH @sub 4@, and NH @sub 3@+CH @sub 4@, and r.f. powers. The S values of CN and NH radicals range from 0-0.15 and 0.8-0.9, respectively, and show very little dependence on the gas compositions and applied power. In contrast, the S values of NH @sub 2@ decrease from 0.8 ±0.1 to 0.4 ±0.1 when the CH @sub 4@ fraction in the plasma is increased. The essentially 100% scatter measured for NH suggests that NH is not a major deposition precursor in these plasmas. The effects of ion energies on S values were analyzed using DC bias of the substrate. The S values show an obvious dependence on the bias voltage. The r.f. inductively coupled plasmas during the film deposition have also been characterized during the film deposition by optical emission spectroscopy and mass spectrometry. Ion energy distributions were also measured using mass spectrometry. Results indicate that energetic ions are important in surface production of the species studied with IRIS. X-ray photoelectron spectroscopy analysis of deposited films showed the N content increases with increasing the N @sub 2@ or NH @sub 3@ fractions of reactive gases. The mechanisms for film deposition in these carbon nitride systems will be discussed in light of our gas-phase, surface, and gas-surface interface data.