Exemplary methods for selective etching of semiconductor materials may include flowing a fluorine-containing precursor into a processing region of a semiconductor processing chamber. The methods may also include flowing a silicon-containing suppressant into the processing region of the semiconductor processing chamber. The methods may further include contacting a substrate with the fluorine-containing precursor and the silicon-containing suppressant. The substrate may include an exposed region of silicon nitride and an exposed region of silicon oxide. The methods may also include selectively etching the exposed region of silicon nitride to the exposed region of silicon oxide.