Semiconductor devices and methods of manufacture

A system and methods of forming a dielectric material within a trench are described herein. In an embodiment of the method, the method includes introducing a first precursor into a trench of a dielectric layer, such that portions of the first precursor react with the dielectric layer and attach on sidewalls of the trench. The method further includes partially etching portions of the first precursor on the sidewalls of the trench to expose upper portions of the sidewalls of the trench. The method further includes introducing a second precursor into the trench, such that portions of the second precursor react with the remaining portions of the first precursor to form the dielectric material at the bottom of the trench.