Adsorption and thermal decomposition of N2O on Si(100) : electron energy loss spectroscopy and thermal desorption studies

Abstract The interaction of N 2 O with the Si(100) surface has been studied by using high-resolution electron energy-loss spectroscopy and thermal desorption spectroscopy. When the Si(100) surface is exposed to N 2 O at 90 K, N 2 O is, initially, partially dissociated into N 2 and O. While O is inserted into the SiSi bond to form a SiOSi species, N 2 desorbs immediately after the dissociation. Two types of molecularly chemisorbed species (α- and β-N 2 O) are found on the partially oxidized surface. The NO and NN stretching vibrations of the α-N 2 O are observed at 175 and 288 meV, respectively, and this species is decomposed into atomic O and desorbing N 2 at 110 K. The β-N 2 O whose NN stretching vibration is observed at 203 meV is decomposed at 150 K. The β-N 2 O is considered to be adsorbed via its terminal N atom, probably with the 2π and 3π orbitals. With increasing exposure, N 2 O multilayers are formed on this surface at 90 K. Neither the adsorption of N 2 O nor the formation of SiOSi species are observed when the Si(100) surface is exposed to N 2 O at 300 K.