ADSORPTION REACTIONS OF TI SI(001) BY VARIABLE-TEMPERATURE STM/

Monatomic adsorption of ii on the Si(001)-2 x 1 surface has been obser ved by variable-temperature scanning tunneling microscopy. A Ti alum i s reversibly converted between two precursor states which are pedestal site adsorption and a highly mobile state between the dimer rows. The final stale, that is a vacancy site adsorption, is formed only from t he pedestal site adsorption inducing ejection of Si dimer atoms. The q uantitative and qualitative evaluation of the site conversion reveals that the adsorption behavior is highly affected by the local bonding p roperties of Ti with the Si 2 x 1 reconstruction.