Implementations described herein generally relate to methods for dielectric gap-fill. In one implementation, a method of depositing a silicon oxide layer on a substrate is provided. The method comprises introducing a cyclic organic siloxane precursor and an aliphatic organic siloxane precursor into a deposition chamber, reacting the cyclic organic siloxane precursor and the aliphatic organic siloxane precursor with atomic oxygen to form the silicon oxide layer on a substrate positioned in the deposition chamber, wherein the substrate is maintained at a temperature between about 0° C. and about 200° C. as the silicon oxide layer is formed, wherein the silicon oxide layer is initially flowable following deposition, and wherein a ratio of a flow rate of the cyclic organic siloxane precursor to a flow rate of the aliphatic organic siloxane precursor is at least 2:1 and curing the deposited silicon oxide layer.