Abstract We describe here the first use of HN 3 as a nitrogen precursor for forming germanium nitride. Its chemistry, as well as that of NH 3 and N 2H 4 on Ge(100) have been investigated using HREELS, AES, LEED, and TDS. All three molecules were found to adsorb molecularly on Ge(100) at low temperatures. Upon warming the substrate, both NH 3 and N 2H 4 desorb molecularly, at roughly 275 and 325 K respectively. In contrast, HN 3 begins to dissociate at about 375 K, desorbing N 2 and leaving NH groups on the surface. Further heating to 575 K causes the hydrogen to desorb. Repeated saturation dose/anneal cycles can be used to thermally grow a thin film of germanium nitride. The nitride begins to decompose at about 750 K and is completely desorbed by 875 K.