| 1. |
- Larsen, A. Nylandsted, et al.
(författare)
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E center in silicon has a donor level in the band gap
- 2006
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 97:10, s. 106402/1-106402/4
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Tidskriftsartikel (refereegranskat)abstract
- It has been an accepted fact for more than 40 years that the E center in Si (the group-V impurity-vacancy pair)-one of the most studied defects in semiconductors-has only one energy level in the band gap: namely, the acceptor level at about 0.45 eV below the conduction band. We now demonstrate that it has a second level, situated in the lower half of the band gap at 0.27 eV above the valence band. The existence of this level, having a donor character, is disclosed by a combination of different transient-capacitance techniques and electronic-structure calculations. The finding seriously questions some diffusion-modeling approaches performed in the past.
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| 2. |
- Pellegrino, P., et al.
(författare)
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Separation of vacancy and interstitial depth profiles in proton- and boron-implanted silicon
- 2002
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Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - 0168-583X .- 1872-9584. ; 186, s. 334-338
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Tidskriftsartikel (refereegranskat)abstract
- A new experimental method of studying shifts between concentration-versus-depth profiles of vacancy-type and interstitial-type defects in ion-implanted silicon is demonstrated. The concept is based on deep level transient spectroscopy (DLTS) measurements utilizing the filling pulse variation technique. The vacancy profile. represented by the vacancy-oxygen center and the interstitial profile, represented by the substitutional carbon-interstitial carbon pair, are obtained at the same sample temperature by varying the duration of the filling pulse, Thus the two profiles can be recorded with a high relative depth resolution, Point defects have been introduced in low doped float zone n-type silicon by implantation with 6 MeV boron ions and 1.3 MeV protons at room temperature, using low doses. For each implantation condition the peak of the interstitial profile is shown to be displaced by similar to 0.5 mum towards larger depths compared to that of the vacancy profile. This shift is primarily attributed to the preferential forward momentum of recoiling Si atoms, in accordance with theoretical predictions.
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