Technological Methods of Forming Thin Semiconductor Layers. Part 2

Abstract

Features and basic technological methods of formation of thin layers of semiconductor materials in a vacuum with the method of thermal spraying in a quasi-closed volume are analyzed. The disadvantages of thermal spraying of thin films of multicomponent semiconductor compounds in an open vacuum are indicated. The designs of special collapsible evaporator chambers for thermo-vacuum sputtering in a quasi-closed volume containing the raw material and substrate in quasi-isolated conditions are presented. They allow to create and manage the necessary temperature corrections between the evaporator, lining, walls and other structural elements. The designs of special collapsible evaporator chambers for thermo-vacuum sputtering in a quasi-closed volume containing the raw material and substrate in quasi-isolated conditions are presented. They allow to create and manage the necessary temperature corrections between the evaporator, lining, walls and other structural elements. It is shown that the spatial temperature distribution in the discussed constructs provides the evaporation (sublimation) of the source material, the reflection of vapor from the heated walls, the intensive exchange interaction between the gas phase and the condensation surfaces and the prevailing condensation on the substrate surface, which contributes to the diffusion mechanism of the transfer of matter and to the thermodynamically balanced growth process for films. It is shown that for all modifications, to a greater or lesser extent, the conditions for the isolation of the localized volume and the equilibrium of the condensation process are fulfilled by creating the necessary temperature gradient. It is indicated that it is problematic to use such structures for mass production due to their complexity and technological features. That is why the method of thermal spraying of thin films in the quasi-closed volume is most often used in the production of epitaxial monocrystalline layers for scientific research and experimental development, and for industrial production it is very effective to develop methods for obtaining thin films, which from one hand combine universality of thermal spraying in opened vacuum and from another hand allow to bring the processes of evaporation (sublimation) and condensation closer to thermodynamic equilibrium, for example, various types of “hot walls”. It is noted that the analyzed methods or their modifications are these necessary methods of creating thin-film semiconductor structures with predetermined properties.