CHARACTERISTICS OF EVAPORATED STEARIC-ACID FILMS PREPARED BY THE HOT WALL TECHNIQUE

The hot wall technique (HWT) was used to prepare evaporated films of stearic acid at the furnace temperature of 311-381 K, the substrate temperature of 278-339 K, and ambient pressure of 6 × 10-6 torr. In some experiments a flip-flop (growth interruption scheme) was used to control the film growth rate at given combinations of the furnace and substrate temperatures. Glass slides were used for the substrate. The structure of the film was analysed by X-ray diffractometry. It was found that long chain axes in the stearic acid film were preferentially oriented normal to the substrate plane when the growth rate was low, and differences in temperatures between the furnace and substrate were small. On the contrary, the preferred chain-axes orientation became parallel to the substrate at higher growth rates and larger temperature differences between the furnace and substrate. A Monte Carlo simulation was made on the film growth processes in HWT. We observed a good agreement between the measured and simulated distributions of the film thickness. © 1990.