THE ADSORPTION OF HYDROGEN, DIGERMANE, AND DISILANE ON GE(111) - A MULTIPLE INTERNAL-REFLECTION INFRARED-SPECTROSCOPY STUDY

The adsorption of hydrogen, digermane, and disilane on the Ge(111) surface has been investigated using multiple internal reflection infrared spectroscopy (MIRIRS). Adsorption of atomic hydrogen on Ge(111) leads to the production of GeH3, GeH2, and GeH at low temperatures (less-than-or-equal-to 150K), and strictly a monohydride at higher temperatures (greater-than-or-equal-to 400K). Atomic H occupies primarily a single GeH adsorption site at 500K, whereas a range of monohydride adsorption sites exists at lower temperatures. At temperatures below 300K, GeH production dominates H atom exposure, with minor production of the higher hydrides, while dissociative adsorption of Ge2H6 favors formation of GeH2 and GeH3. Similar behavior is observed for disilane adsorption, with formation of SiH3 and SiH2 below 300K and SiH above this temperature. Molecular and dissociative adsorption are competitive processes at 110-140K. Decomposition of all surface hydrides occurs by 600K.