Core-Level Photoemission Spectroscopy of Metal and Semiconductor Interfaces
Abstract
The goal of the group from NCSU-Rutgers (Jack Rowe's group, in collaboration with Ted Madey) is to use core level photoemission to study inerfaces and surfaces of electronic materials and metallic systems. There is also an effort to upgrade this beamline to a Spherical Grating Monochromator (SGM) which is being performed in collaboration with Steve Hulbert of NSLS. Since gate oxides used in current devices have continued to decrease in thickness with corresponding improvements in oxide growth, processing and device properties, we have reinvestigated the issue of the interface of SiO2/Si(111) using the current state-of-the-art methods of gate oxide growth. The Si(2p) core level has a relatively large chemical shift which is nearly ideal for identifying the interface oxide states with SXPS. The bulk Si(2p) binding energy for Si(111) is ^99.3 eV and the bulk Si(2p) oxide value for film thickness 30 A SiO2 is ^103.7eV. 1 The binding energies of the three interface-shifted peaks are intermediate between these values. These have been assigned by Himpsel et al. 2 as the intermediate oxidation states of Si atoms usually labeled Si1+, Si2+ and Si3+ with the bulk Si peak labeled SiO and the bulk oxide peak labeled Si4+. BeamlineU4A has just completed the first phase of a major upgrade. As part of the DOE Facilities Initiative, we are adding spherical gratings and a movable exit slit to the beamline, replacing the toroidal gratings and fixed slits to achieve a spherical toroidal grating monochromator (STGM). More detailed information has become a vital concern in correlators photoemission studies that were started a few years ago. For example, the reconstruction of Si surfaces results in poorly resolved surface-atom core-electron binding-energy shifts that are not readily determined without reliable information about the instrumental width.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 31, 1999
- Accession Number
- ADA379039
Entities
People
- J. E. Rowe
- T. E. Madey
Organizations
- Rutgers University–New Brunswick