Ternary nanocomposite silicon carbonitride (Si-C-N) ceramic coatings have shown potential for wear resistance, oxidation resistance, hardness, tunable band gap, and chemical inertness applications. A systematic investigation on the deposition of Si-C-N nanocomposite coatings by sputtering under varying deposition conditions such as chamber pressure, substrate temperature by structural, nanoindentation, and microstructural studies of optimized condition has been presented. Significant role of different deposition parameter on the mechanical and structural properties were observed. The structural characterizations of the coatings were carried out using Fourier transformed infra red (FTIR), transmission electron microscopy, Raman spectroscopy, and field emission scanning electron microscope. An increase in argon-nitrogen pressure in the range of 1-5 Pa led to lowering of particle size and surface smoothening and growth of hard phases of beta-C3N4 and beta-Si3N4. An increase in substrate temperature from room temperature to 500 degrees C led to nucleation and growth of hard phases of beta-C3N4 and Si3N4 in the amorphous Si-C-N matrix. The nanoindentation studies showed the variation in hardness and Young's modulus from 8 to 22 GPa and from 100 to 240 GPa, respectively, dependent on the deposition conditions. The FUR studies confirmed the presence of C-N, Si-N, Si-Si, Si-O, and Si-C in different films. (c) 2010 American Vacuum Society. [DOI: 10.1116/1.3420430]