Thermal agglomeration of ultrathin silicon-on-insulator layers: Crystalline orientation dependence

The thermal agglomeration of ultrathin silicon-on-insulator (SOI) layers with different crystalline orientations [(110)-, (100)-, and (111)-oriented SOI layers] is reported. (110) SOI agglomeration leads to the formation of Si island arrays along < 221 > and < 332 > directions, while (100) and (111) SOI agglomerations result in Si island arrays in < 310 > directions and Si wires in < 121 > directions, respectively. The {311} facets mainly determine the direction of the agglomerated shape, whereas the symmetric and asymmetric facet properties are responsible for Si island and wires formation, respectively. These results indicate that Si islands or wires can be formed in certain directions by selecting the appropriate SOI crystalline orientation.