Methods for gapfilling semiconductor device features, such as high aspect ratio trenches, with amorphous silicon film are provided. First, a substrate having features formed in a first surface thereof is positioned in a processing chamber. A conformal deposition process is then performed to deposit a conformal silicon liner layer on the sidewalls of the features and the exposed first surface of the substrate between the features. A flowable deposition process is then performed to deposit a flowable silicon layer over the conformal silicon liner layer. A curing process is then performed to increase silicon density of the flowable silicon layer. Methods described herein generally improve overall etch selectivity by the conformal silicon deposition and the flowable silicon deposition two-step process to realize seam-free gapfilling between features with high quality amorphous silicon film.