Orientation of films prepared by the evaporation of poly(dimethyl silane)

Abstract

This paper describes highly oriented films prepared by the evaporation of poly(dimethyl silane). The specimens are prepared at various evaporation speeds and substrate temperatures. The polymer is divided into species of about 2 nm length on the evaporation heater, and the species recrystallize on the substrate. The structure and orientation of the films are investigated using wide-angle X-ray diffraction and ultraviolet absorption methods. The substrates used are single-crystal silicon (100) for the X-ray diffraction measurement and fused silica for the ultraviolet absorption measurement. The polymer exhibits the same orientation on both substrates. It is found that most of the silicon chains are perpendicular to the substrate surface in the film prepared under the condition whose growth rate is lower than 20 nm min-1. On increasing the substrate temperature, the number of silicon chains whose orientation is normal to the substrate surface increases.