CHARACTERIZATION OF TERMINATION LAYER OF SIGE SYSTEM THROUGH SIGNATURES OF SI-O AND GE-O SPECIES

In this paper, we describe a novel method of employing the phenomenon of oxygen chemisorption for surface atom identification on a SiGe surf ace. On a clean Si(100). dosing 100 L O-2 (1 Langmuir = 1 s at 1 x 10( -6) Torr) at room temperature gives rise to peaks at 7 and 10.2 eV in ultraviolet photoelectron spectroscopy with He I excitation (HeI UPS) and O Is is observed at 532.3 eV in X-ray photoelectron spectroscopy ( NPS). Corresponding spectra for Ge(100) are a single peak at 5.2 eV in HeI UPS and O 1s at 531.3 eV. These signature spectra of Si-O and Ce- O species have been effectively employed for unambiguous characterizat ion of the termination laver of SiGe surfaces. Upon dosing at room tem perature, on a sample prepared by depositing 5 Angstrom Ge on Si(100) at 500 degrees C, oxygen bonds with Ge atoms are forming GeO, exclusiv ely. This indicates surface termination entirely by Ge atoms. Oxygen a dsorption at room temperature, on a sample prepared by codeposition of Ge and Si (total 5 Angstrom) onto Si(100) at 550 degrees C, forms a m ixed oxide suggesting a surface termination by both Gt and Si atoms.