Embodiments disclosed herein generally include methods for forming porous low k dielectric films. In one embodiment, a method of forming a porous low k dielectric film on a substrate using PECVD and in situ radical curing in a processing chamber is disclosed. The method includes introducing radicals into a processing region of the processing chamber, introducing a gas mixture into the processing region of the processing chamber, forming a plasma in the processing region and depositing the porous low k dielectric film on the substrate.