A method of depositing dielectric material into sub-micron spaces and resultant structures is provided. After a trench is etched in the surface of a wafer, a liner layer preferably is deposited into the trench. An anisotropic plasma process is then performed on the trench. A silicon layer may be deposited on the base of the trench during the plasma process, or the plasma can treat the liner layer. The trench is then filled with a spin-on precursor. A densification or reaction process is then applied to convert the spin-on material into an insulator, and oxidizing the silicon rich layer on the base of the trench. The resulting trench has a consistent etch rate from top to bottom of the trench.