In this paper, preparation and characterization of a-SiNx thin films deposited by LPCVD method from free radicals of TCS and NH3 gaseous system were investigated. These radicals are made by passing each of the precursor gases separately over Pt-Ir/Al2O3 catalyst at the temperature of 600 ᐤC. Kinetics of this process was investigated at different total pressures, NH3/TCS flow rate ratios and temperatures. Surface topography and chemical concentrations were studied by Ellipsometry, XXPS, AFM and ADP. Our analyses of the performed experiments indicated that at the temperatures between 730 ᐤC and 830 ᐤC, the growth rate of thin films follows an Arrhenius behavior with activation energy of 166.3 KJ.mol-1. The measured H2 contamination in a-SiNx thin films is 1.05 at%, which is 17 times lower than the corresponding contamination in the films produced by PECVD and 3.4 times lower than the contamination in the LPCVD thin films with SiH4 or DCS and NH3. The created surface topography of the prepared films is smooth and uniform.

Keywords: Gaseous free radicals, Pt-Ir/Al2O3 catalyst, a-SiNx, TCS, LPCVD.

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