Study of Interfacial Chemistry between Metals and their Effect on Electronic Systems
Abstract
A number of results are summarized in this report. Many of these relate to the Advanced Unified Defect Model outlined in the previous semi-annual report. In this context, the modeling results help explain recent results on a model ohmic contact from Waldrop. This is important in that it appears that a new mechanism for ohmic contacts on GaAs is possible. Another area of research is that of heterojunctions. In one set of experiments, new techniques involving polarization dependent SEXAFS (Surface Extended X ray Absorption Fine Structure) measurements were developed and applied to determine the lattice constant of Si on GaAs perpendicular to the interface as a function of Si thickness. The results indicate dislocation formation at these 4% lattice mismatched heterojunctions at Si thicknesses less than previously predicted. Our work on Si/GaAs has allowed us to critically examine the roles of materials perfection and measurements difficulty in determining offsets using PES. We find that differences in reported results are likely due to poor misinterpretation of experimental data rather than a variation of offset due to materials imperfection. A new soft X ray source allows us to use this tool with high surface sensitivity in PES. The effects of annealing of Ti/GaAs give important insights for this practically important system. Studies of As/GaAs gives more insight into the nature of Fermi level pinning on GaAs.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 1987
- Accession Number
- ADA195261
Entities
People
- I. Lindau
- William E. Spicer
Organizations
- Stanford University