Embedded carbon bridges in low-k PECVD silicon carbonitride films using silazane precursors

Low-k, carbon-rich SiCxNy films for diffusion barrier applications have been fabricated by plasma-enhanced chemical vapor deposition (PECVD) using silazanes as the single-source precursor. Linear and cyclic silazane precursors with vinyl groups yield SiCxNy films with carbon bridges, namely ethylene bridges (Si-CH2-CH2-Si) and methylene bridges (Si-CH2-Si), which are readily formed and embedded with the Si-N(-C) matrix. A SiCxNy film of low k = 3.2 is achieved by successful incorporation of ethylene bridge embedded within the Si-N(-C-x) network by using a linear silazane precursor. Also, for these silazanes-deposited SiCxNy films at a fixed dielectric constant below 4.2, cyclic silazane, VSZ (1,3,5-trimethyl-1,3,5-trivinylcyclotrisilazane) produces films of higher film density and modulus, compared to those by a linear silazane precursor. (C) 2019 The Japan Society of Applied Physics