Lowering the Schottky Barrier at Metal or Silicide/Si Interfaces to Extend the Range of Infrared Detectors
Abstract
Si and group IV based Schottky barriers (SB) below about 0.2eV are of considerable technological importance since detectors based upon them will be able to probe deep into the infrared while maintaining well established processing techniques. Investigations relating to this problem have been carried out using ultra-high vacuum techniques and X-ray photoelectron spectroscopy. Two approaches have been pursued, one by tailoring the interface geometric and hence electronic structure and the other by using a reduced band gap material. The systems studied were Sn on Si(111) and Pt on Ge(111). Sn invokes several surface reconstructions on Si(111) one of which, the 2 square root of 3 structure has an associated electronic structure with the Fermi level situated (0.14 +/- 0.10)eV above the valence band maximum (VBM). This means that the corresponding p-type SB is also (0.14 +/- 0.10) eV, well below the value of 0.22eV found at the PtSi/ Si(100) interface. Similarly, when Pt was deposited onto Ge(100), the Fermi level was positioned (0.12 +/- 0.04)eV above the VBM, again resulting in a p- type SB significantly lower than that at the PtSi/Si(100) interface. Chemical interactions at the Pt/Ge interface are discussed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1993
- Accession Number
- ADA277253
Entities
People
- C. L. Griffiths
- R. H. Williams
Organizations
- University of Wales