Methods of forming semiconductor devices are provided herein. In some embodiments, a method of forming a semiconductor device may include providing a substrate having an oxide surface and a silicon surface; forming a nitrogen-containing layer on exposed portions of both the oxide and silicon surfaces; and oxidizing the nitrogen-containing layer to selectively remove the nitrogen-containing layer from atop the oxide surface. In some embodiments, an oxide layer is formed atop a remaining portion of the nitrogen-containing layer formed on the silicon feature. In some embodiments, the oxide surface is an exposed surface of a shallow trench isolate region (STI) disposed adjacent to one or more floating gates of a semiconductor device. In some embodiments, the silicon surface is an exposed surface of a silicon or polysilicon floating gate of a semiconductor device.