| Autor: |
Muller, G., Hellmich, W., Krotz, G., Kalbitzer, S., Greaves, G. N., Derst, G., Dent, A. J., Dobson, B. R. |
| Zdroj: |
Philosophical Magazine B; 1996, Vol. 73 Issue: 2 p245-259, 15p |
| Abstrakt: |
Substitutional (B, P, As and Ga) and interstitial (K) dopants have been incorporated into H-free amorphous Si (a-Si) films produced by ion beam amorphization of crystalline silicon material. X-ray absorption fine-structure, photothermal deflection spectroscopy and electronic transport measurements have been performed on these films to monitor the annealing-induced ordering phenomena around the implanted dopant impurity sites. We find that, in thermally relaxed a-Si, substitutional dopant impurities have a strong tendency to enter the Si random network in the form of threefold-coordinated, electrically inactive, alloying sites. It is shown that the bonding constraints associated with these sites retard the structural relaxation process of the a-Si films and the crystallization of the a-Si network in the immediate neighbourhood of these sites. In agreement with previous work, we find that high-defect-density a-Si films can be electrically doped with interstitial K impurities. In such interstitially doped material, excess dangling-bond densities are observed which are likely to arise from a charge-induced bond-breaking mechanism. |
| Databáze: |
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