Embodiments disclosed herein generally include an apparatus for radical-based deposition of dielectric films. The apparatus includes a processing chamber, a radical source coupled to the processing chamber, a substrate support disposed in the processing chamber, and a dual-channel showerhead disposed between the radical source and the substrate support. The dual-channel showerhead includes a plurality of tubes and an internal volume surrounding the plurality of tubes. The plurality of tubes and the internal volume are surrounded by one or more annular channels embedded in the dual-channel showerhead. The dual-channel showerhead further includes a first inlet connected to the one or more channels and a second inlet connected to the internal volume. The processing chamber may be a PECVD chamber, and the apparatus is capable of performing a cyclic process (alternating radical based CVD and PECVD).