Scanning probe lithography has been used for the first time to grow silicon nitride nanostructures on silicon substrates. The lithography was performed by an atomic force microscope (AFM) placed in an evacuated chamber with a partial pressure of annhydrous ammonia. The silicon nitride nanostructures were grown by negatively biasing the silicon tip with respect to the sample. By changing the environment of the AFM, both silicon oxide and silicon nitride can be grown and subsequently processed.