Provided herein are novel pre-metal dielectric (PMD) integration schemes. According to various embodiments, the methods involve depositing flowable dielectric material to fill trenches or other gaps between gate structures in a front end of line (FEOL) fabrication process. The flowable dielectric material may be partially densified to form dual density filled gaps having a low density region capped by a high density region. In certain embodiments, the methods include further treating at least a portion of the gap fill material after subsequent process operations such as chemical mechanical planarization (CMP) or contact etching.