1. Mechanism of hole inlet closure in shape transformation of hole arrays on Si(001) substrates by hydrogen annealing
- Author
-
Koichi Sudoh, Hitoshi Kuribayashi, Ryosuke Shimizu, and Reiko Hiruta
- Subjects
Azimuth ,geography ,Materials science ,geography.geographical_feature_category ,Annealing (metallurgy) ,Metallurgy ,Pattern formation ,Geometry ,Anisotropy ,Mirror symmetry ,Microstructure ,Inlet ,Surface energy - Abstract
We investigated the process of the hole inlet closure in surface-diffusion-driven transformation of arrays of high-aspect-ratio holes on Si(001) substrates. The inlet gradually shrinks while keeping the circular shape because of lateral bulging of the inlet surface. We observed complicated top view morphologies reflecting the four-fold symmetry of the Si(001) surface on the inlet surface. Large {111} and {113} facets are formed in the four equivalent azimuths of the [110], while corrugated patterns arise in the four equivalent azimuths of the [100]. Atomic force microscopy observations reveal that the corrugated pattern is composed of three types of small facets, namely, {110} and two {113} in relation of the mirror symmetry. The corrugated pattern formation is due to the geometrical restriction that there is no stable facet between (001) and (010) in the [010] azimuth. The observed morphological evolution is interpreted as surface-diffusion-driven transformation under constraint of the anisotropic surface energy of Si.
- Published
- 2011