An experimental facility to study film growth on liquid phase, condensation and melting in downward-facing substrates

Resumen

Film growth, condensation and melting of materials are very important physical processes, involved in the development of semiconductor related industry processes, alkali metals and their oxides, and recently in nuclear fusion projects. The growth of low melting point thin films via liquid phase epitaxy (LPE) has drawn attention especially for the manufacture of semiconductor compounds containing indium, gallium, tin, lithium and their alloys, all characterized by a low melting point. That allows the growth of films in the liquid phase and subsequent control on crystallization morphology by manipulating quenching conditions.  LPE yields highly crystalline either thin (a few nm) or thick (100s of µm) films with high purity. If LPE is performed in downward-facing substrates, Rayleigh-Taylor instabilities appear, and this effect of gravity in the film growth has not been studied in depth. This paper presents the design, construction and preliminary testing of an experimental facility to study film growth from the liquid phase, and also condensation and melting processes. This facility consists of a thermal evaporator and a substrate holder where samples are placed facing down. The size of the sample holder and the ability to achieve controlled thermal gradients across it, would allow the study of temperature effect in grown films morphology, and also in condensation and melting phenomena such as dripping onset and critical angle for film/drop displacement. Besides, system allows to study condensation modes and surface roughness on the condensation dynamics of liquid films growing from the vapor phase.