The micro-structure transformation of silicon (MSTS), which is a transformation technology for patterning silicon surfaces by hydrogen annealing, is presented for the first time. The transformation was controlled by the parameters of annealing pressure as well as annealing time and temperature. Voids of sub-micrometer regime size can be intentionally formed in the silicon substrates by making use of transformation. Electrical characteristics, such as the reliability of the thin dielectrics formed in the deep trenches, were improved with the aid of the MSTS process, due to the flattening of the inside surface of the trenches and the rounding of the corners. The mechanism of the transformation by MSTS was studied by means of molecular dynamics, which clearly shows the migration of silicon atoms on the surface. MSTS is a promising technology for the fabrication of future integrated circuits in silicon.

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The conduction sites in the main chain of helical polyacetylene (HPA) are arranged in a unique helical configuration, whereas conventional conductive polymers such as cis-polyacetylene and trans-polyacetylene have almost collinearly aligned conduction sites. Here we report the distinctive hole transport properties in HPA caused by the helical structure. Analyses of the hole diffusion with different models of the range of transfer integrals (TIs) reveal that the helical configuration produces multiple conduction paths in HPA. The holes propagate through multiple pathways, avoiding local paths with small TIs. This mechanism suppresses the localization of electronic states in HPA, which is inevitable in conventional one-dimensional conductive polymers.

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