Collisional Transition Probabilities for Rotational Levels of CN (B2Σ+)

Sticking probability of CN(X2Σ+) radicals onto amorphous carbon nitride films formed from the decomposition of BrCN induced by the microwave discharge flow of Ar

The sticking probability, s, of CN(X(2)Σ(+)) radicals onto amorphous carbon nitride (a-CN(x)) films with high [N]/([N]+[C]) ratios (≤0.5) was evaluated. CN(X(2)Σ(+)) radicals were generated from the decomposition of BrCN with the microwave discharge flow of Ar in the two experimental configurations, I and II, where the distance between the tip of the nozzle introducing BrCN is close (≈10 mm) to and distant (≈0.3 m) from the laser-beam path or the Si substrate, respectively. For each configuration, s was evaluated both under the desiccated and H(2)O-added conditions from the number density of CN(X(2)Σ(+)) evaluated from the intensity of the CN(A(2)Π(i)-X(2)Σ(+)) laser-induced fluorescence spectrum calibrated against Rayleigh scattering intensity of Ar, the flow speed measured by a time-resolved emission, and the film mass. The [N]/([N]+[C]) ratios of films were evaluated as 0.4-0.5 and 0.3 in the configurations I and II, respectively, from the compositional analysis using Rutherford back scattering and elastic recoil detection analysis together with the XPS analysis. The variation of s under various experimental conditions was discussed based on the electron densities in the reaction region and the relative density of the hydrogen-termination structures of the film surface.

Measurements of density and sticking probability of CN(X(2)Sigma(+)) radicals by laser-induced fluorescence spectroscopy

CN(X(2)Sigma(+)) radicals were produced by the decomposition of BrCN with the microwave discharge flow of Ar under the conditions of Ar pressure in the range of 0.40-0.70 Torr. The laser-induced fluorescence (LIF) spectra of the CN(A(2)Pi(i)-X(2)Sigma(+)), 4-0, 5-1, and 7-2 bands were observed, and their intensities were calibrated against Rayleigh-scattering intensity by Ar atoms, from which the CN(X(2)Sigma(+)) radical density (n(CN(X))) was determined as (0.67+/-0.25) x 10(18) to (4.42+/-0.83) x 10(18) m(-3). Hydrogenated amorphous carbon nitride (a-CN(x):H) films were formed by depositing the CN(X(2)Sigma(+)) radicals on Si substrates in the same reaction system as LIF. The sticking probability (s) of the CN(X(2)Sigma(+)) radicals onto the a-CN(x):H films was determined by using n(CN(X)), the flow speed, and the weight (w) of a-CN(x):H. The s value was determined as (6.4+/-6.4) x 10(-2) to (2.5+/-1.2) x 10(-2), where the errors are predominantly determined by those in n(CN(X)) and w. The procedure described in the present study will provide a methodology to determine the sticking probability of the precursor radicals of the film formation based on the gas-phase LIF spectroscopy.