Flowable film curing using H2 plasma

Embodiments herein provide methods of plasma treating an amorphous silicon layer deposited using a flowable chemical vapor deposition (FCVD) process. In one embodiment, a method of processing a substrate includes plasma treating an amorphous silicon layer by flowing a substantially silicon-free hydrogen treatment gas into a processing volume of a processing chamber, the processing volume having the substrate disposed on a substrate support therein, forming a treatment plasma of the substantially silicon-free hydrogen treatment gas, and exposing the substrate having the amorphous silicon layer deposited on a surface thereof to the treatment plasma. Herein, the amorphous silicon layer is deposited using an FCVD process. The FCVD process includes positioning the substrate on the substrate support, flowing a processing gas into the processing volume, forming a deposition plasma of the processing gas, exposing the surface of the substrate to the deposition plasma, and depositing the amorphous silicon layer on the surface of the substrate.