Evolution processes in island films grown from single-component melts: The last stage

Abstract

A theory of initial stages in island film growth from single-component melts is presented. A hypothesis on “thermal coalescence (coarsening)”, i.e. the Ostwald ripening of an island ensemble of a new-phase growing from single-component melts on a solid substrate surface, is advanced. The physical sense of the latter involves the fact that under specific conditions (at a late stage of the process) there is a common thermal field in the melt layer containing an ensemble of islands adjacent to a substrate surface. Islands with a radius below the critical value are dissolved in the field, whereas those with a radius exceeding the critical value grow. In the course of their growth and dissolution, heat of crystallization is evolved and absorbed. Supercooling of the melt drops accordingly and the islands interact with each other, similar to the case in which there is Ostwald ripening of growing islands due to the arrival of a diffusion substance. A complete set of equations describing the above process is derived and solved, and asymptotic relationships are found.