Characterization of Oxide Formed on Silicon by Exposure to Atomic Oxygen in Space
Abstract
The oxide formed on silicon by exposure to space on the long duration exposure facility (LDEF) has been examined using variable angle spectroscopic ellipsometry (VASE), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The position of the silicon specimen on the satellite resulted in the formation of an oxide whose thickness varied with distance along the sample surface. Each transverse section of the surface was studied separately and compared to a region on the sample shielded from the oxygen flux in space by an aluminum bar. Film thickness and composition of the oxide were determined by a least square fit of the VASE data to a model surface using an effective medium approximation. The results revealed a nonporous oxide film with a thickness that increased from 350 A to 1200 A almost linearly along the sample. Furthermore, all of the experiments revealed an oxygen deficiency that increases with film thickness. Several other techniques were also performed on the sample to confirm these results. These results can be used to identify some of the oxide deposition parameters which occurred in the environment of the LDEF. Variable angle spectroscopic ellipsometry (VASE), Silicon, Atomic oxygen, X-ray photoelectron spectroscopy (XPS), Oxide films, Fourier transform infrared, Rutherford backscattering spectroscopy (RBS), Long duration exposure, reflectance, Spectroscopy, facility (LDEF), Ellipsometry, Space environments.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1992
- Accession Number
- ADA249787
Entities
People
- Judith S. Brodkin
- Louise C. Sengupta
- Paul L. Sagalyn
- Wolfgang Franzen