Amorphous-to-polycrystalline phase transformations in Sn-implanted silicon
- PDF / 1,090,693 Bytes
- 10 Pages / 593.28 x 841.68 pts Page_size
- 90 Downloads / 208 Views
An amorphous-to-fine-grain-polycrystalline phase transformation has been observed during annealing of Sn-implanted Si when the peak Sn concentration exceeds about 2 at. %. At lower Sn concentrations, epitaxial growth is retarded in (100) Si but proceeds to completion with a large fraction of Sn residing on substitutional lattice sites. As the Sn concentration is increased, epitaxy is pre-empted by the sudden transformation of the near-surface Sn-doped region into polycrystalline Si. The time required to initiate the transformation is temperature dependent and is characterized by an activation energy of —1.7 eV. Rapid redistribution of Sn has been observed to accompany the transformation. Our observations are shown to be consistent with a melt-mediated crystallization process which is rate limited by Sn diffusion and precipitation in amorphous Si.
I. INTRODUCTION
In previous studies, we have shown that high dose In-implanted Si undergoes an intriguing amorphous-topolycrystalline phase transformation at temperatures below that at which solid phase epitaxial growth (SPEG) proceeds.1'2 Furthermore, our observations indicated that (i) the transformation occurred extremely rapidly, compared with the rate of solid phase crystallization; (ii) the grain size was very small, typically
Data Loading...
