SIZE EFFECTS IN THE EPITAXIAL REALIGNMENT OF POLYCRYSTALLINE SILICON FILMS ONTO SI SUBSTRATES

The epitaxial realignment of As-doped polycrystalline silicon layers has been investigated by varying the dimensions of the contact area with the crystalline silicon substrate. Rectangular strips of width in the 0.2-100 mum range and length in the mm range were used. In the 1-100 mum strips the realignment proceeds by the two-dimensional growth of epitaxial columns, while in the 0.2-0.3 mum strips by the one-dimensional growth. The experimental realigned fractions quantitatively follow the trend predicted by the classical model of nucleation and growth in two and one dimension, respectively. The growth kinetics is slowed down in the small width geometry and the thermal budget to realign the films increases.