Embodiments of the present disclosure generally relate to processes for forming silicon- and boron-containing films for use in, e.g., spacer-defined patterning applications. In an embodiment, a spacer-defined patterning process is provided. The process includes disposing a substrate in a processing volume of a processing chamber, the substrate having patterned features formed thereon, and flowing a first process gas into the processing volume, the first process gas comprising a silicon-containing species, the silicon-containing species having a higher molecular weight than SiH4. The process further includes flowing a second process gas into the processing volume, the second process gas comprising a boron-containing species, and depositing, under deposition conditions, a conformal film on the patterned features, the conformal film comprising silicon and boron.