| EPSRC Reference: |
GR/H74742/01 |
| Title: |
FABRICATION OF SEMICONDUCTING BFESI2/SI HETEROSTRUCTURES BY ION BEAM SYNTHESIS |
| Principal Investigator: |
Kirkby, Professor KJ |
| Other Investigators: |
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| Researcher Co-Investigators: |
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| Project Partners: |
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| Department: |
Sch of Electronics & Physical Sciences |
| Organisation: |
University of Surrey |
| Scheme: |
Standard Research (Pre-FEC) |
| Starts: |
01 May 1993 |
Ends: |
30 April 1996 |
Value (£): |
127,858
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| EPSRC Research Topic Classifications: |
| Optoelect. Devices & Circuits |
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| EPSRC Industrial Sector Classifications: |
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| Panel History: |
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Summary on Grant Application Form |
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Optimisation of the implantation and annealing conditions for the fabrication of high quality FeSi2 layers using Ion Beam Synthesis (IBS). Analysis of the processes governing FeSi2 formation and the mechanisms responsible for the transitions between the semiconducting , metallic a and metastable g phases. Determination of the magnitude and nature of the band gap in IBS FeSi2/n-Si. Evaluation of the electrical properties of the FeSi2/n-Si and aFeSi2/n-Si interfaces. Study of how the band gap of FeSi2 can be modified by the addition of alloying impurities (Co, In, Al).Progress: Fabrication of high quality polycrystalline layers of FeSi2 and aFeSi2. Determination of a direct band gap of 0.87eV for FeSi2 using optical absorption measurements. Measurement of a photoluminescence (PL) peak at 1.54-m with a FWHM of 2.9meV, at 10K, for IBS FeSi2 layers annealed at 920C for 18 hours. For continuous layers of FeSi2 the PL signal is normally lost above 40K. However, by using a hydrogen plasma treatment or hydrogen plasma immersion ion implantation the PL signal is retained up to 200K. Similarly, when small precipitates (~50+) of FeSi2 are formed, PL is observed at much higher temperatures. The PL intensity is also increased with respect to samples where the FeSi2 layer is continuous. Measurement of a barrier height of 0.670.05eV and ideality factor of 1.05 for FeSi2/n-Si diodes at 300K, indicating that thermionic emission is the main current transport mechanism across the barrier for these near ideal p+-n diodes. Measurement of the temperature dependence of the I-V characteristics for FeSi2/n-Si diodes - these show that below 150K deviations from ideal heterojunction diode behaviour are observed. Measurement of a breakdown voltage of -20V and finding that breakdown is principally caused by avalanche mechanisms. Measurement of a barrier height of 0.590.01eV and ideality factor of 1.06 for aFeSi2/n-Si diodes at 300K, indicating that thermionic emission is the main current transport mechanism across the barrier for these near ideal Schottky barrier diodes. Understanding the formation mechanisms of structures where both Co and Fe are implanted and determining that epitaxial structures can be fabricated when Co is implanted first. When Fe is implanted first the layers are polycrystalline. Growth of high quality epitaxial layers of FeSi2 by implanting Fe into an epitaxial CoSi2 layer. Determination of how the presence of Co effects the B to a phase transition temperature for FeSi2. Measurement of electroreflectance from FeSi2/n-Si diodes. 20 Journal & conference papers (several invited).
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Key Findings |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Potential use in non-academic contexts |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Impacts |
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| Description |
This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk |
| Summary |
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| Date Materialised |
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Sectors submitted by the Researcher |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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| Project URL: |
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| Further Information: |
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| Organisation Website: |
http://www.surrey.ac.uk |