A method for forming a high aspect ratio feature is disclosed. The method includes depositing one or more silicon oxide/silicon nitride containing stacks on a substrate by depositing a first film layer on the substrate from a first plasma and depositing a second film layer having a refractive index on the first film layer from a second plasma. A predetermined number of first film layers and second film layers are deposited on the substrate. The first film layer and the second film layer are either a silicon oxide layer or a silicon nitride layer and the first film layer is different from the second film layer. The method further includes depositing a third film layer from a third plasma and depositing a fourth film layer on the third film layer from a fourth plasma. The fourth film layer has a refractive index greater than the first refractive index.