Single source precursors for plasma-enhanced CVD of SiCN films, investigated by mass spectrometry

For plasma-enhanced (PE) CVD of SiCN thin films, hexamethyldisilazane (HMDS) and bis(trimethylsilyl)carbodiimide (BTSC) were selected as single source precursors and investigated by mass spectrometry. Based on their fragmentation patterns, X-NSi(CH3)2 with X=H (HMDS) or X=CN (BTSC) are postulated as film forming species. Their Si : N ratio is identical with that of the related SiCN thin films. H2, CH4, and C2H6 are found in the processing gas mixture during PECVD.