Melt Drops Movement Over Semiconductor Surfaces Controlled by Electric Field

Abstract

The problems of molten zones formation and their subsequent migration over material surface are of interest from the viewpoint of developing novel technological methods of forming microelectronic structures. Such drops can be used as primary working elements of microlenses and reflectors, displays, weighers. The aim of this work was experimental studying processes of electromigration of molten silver- and aluminum-based inclusions over surfaces of germanium and aluminum semiconductor crystals. The issues of formation and motion of molten drops over the surfaces of silicon and germanium semiconductor crystals are considered within the framework of the electrocapillary approach. It is shown by an example of Ge-Ag and Si-Al systems that accelerated migration is related to the contribution of an electrocapillary component that relates surface tension force of melt drops to electric potential difference at the interface. The experiment consisted in applying metal grain to the surface of the samples and vacuuming the chamber where excessive pressure and the surface temperature were created. Migration of inclusions by powerful current pulses was initiated. An analysis of the effect of direct current on a drop of melt deposited on the surface of a crystalline matrix was made. An analysis of the droplet composition was carried out using the AES method, the results of which showed the relationship between silver and germanium concentrations. Quantitative evaluations are given for migration rates in systems under direct current flow as well as under pulsed current loads. During the experiment, it was found that the energy required to detach the droplet from the rigid matrix was not consumed. The value of the surface charge transfer density was estimated. The results of the work can be used to develop new technological methods for the formation of microelectronic structures and their use for practical purposes.