A method of substantially uniformly removing silicon oxide is disclosed. The silicon oxide to be removed includes at least one cavity therein or more than one density or strain therein. The silicon oxide having the at least one cavity or more than one density or strain is exposed to a gaseous mixture of NH3 and HF and heated, to substantially uniformly remove the silicon oxide. A method of removing an exposed sacrificial layer without substantially removing exposed isolation regions using the gaseous mixture of NH3 and HF and heat is also disclosed, as is an intermediate semiconductor device structure that includes a semiconductor substrate, a sacrificial layer overlying the semiconductor substrate, a diffusion barrier overlying the sacrificial layer, and exposed isolation regions.