Deposition chemistry and structure of plasma-deposited silicon nitride films from 1,1,3,3,5,5-hexamethylcyclotrisilazane

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Abstract
Silicon nitride films were deposited in an rf glow discharge from various mixtures of NH3, H2, and N2 with 1,1,3,3,5,5-hexamethylcyclotrisilazane (HMCTSZN). Fourier transform infrared spectroscopy, Rutherford backscattering spectroscopy, and proton magnetic resonance spectroscopy, indicate that the films deposited with NH3 are essentially silicon nitride (<4 at. % C) and contain 25 at. % H , when deposited from dilute HMCTSZN mixtures at elevated rf power. Gas phase neutral mass spectroscopy indicates a relative abundance of NHx radicals produced under these conditions, which actively remove carbon and enhance Si-NH-Si bonding. Films deposited in NH3 /H2 mixtures result in still greater Si–N bonding, since NH3/H2 plasmas are more NHx radical rich than NH3 discharges. Films deposited from H2/HMCTSZN plasmas contain significant carbon concentrations (30–40 at. %), but those formed from dilute HMCTSZN mixtures at elevated rf power are low in H content (21 at. %) and are highly cross-linked due to H abstraction from radicals produced in the discharge.