HREELS STUDIES OF THE CHEMISTRY OF NITROGEN HYDRIDES ON GE(100) - FORMATION OF A SURFACE NITRIDE AT LOW-TEMPERATURES

We describe here the first use of HN3 as a nitrogen precursor for form ing germanium nitride. Its chemistry, as well as that of NH3 and N2H4 on Ge(100) have been investigated using HREELS, AES, LEED, and TDS. Al l three molecules were found to adsorb molecularly on Ge(100) at low t emperatures. Upon warming the substrate, both NH3 and N2H4 desorb mole cularly, at roughly 275 and 325 K respectively. In contrast, HN3 begin s to dissociate at about 375 K, desorbing N-2 and leaving N-H groups o n 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 a bout 750 K and is completely desorbed by 875 K.