Ultra High Vacuum System for Continuous Evaporation of Multilayer Thin Films

Abstract

The apparatus for continuous preparation of multi-layer thin films in ultra-high vacuum has been developed. The system was designed basing on a plan that pre-treated clean samples, being loaded in a side chamber without breaking the fine vacuum of a main chamber, would be able to transfer into the evaporation chamber. The main chamber, 600mm diameter x 1000mm length, has a demountable operating system wich provided with a tunnel oven-assembly, driving and masking mechanisms and others.
Both side chambers, 600mm diameter x 600mm length, being attached to the main chamber have a demountable storage box equipped with heaters for pre-degassing substrates or heat-treating evaporated samples and handling mechanisms by which the substrate holders are drived in or taken out. The ultimate pressure of the main chamber is ensured to be in the 10^-9 Torr region, while the pressure during evaporation process is 1 × 10^-7 Torr. Four layer thin films can be prepared on 75mm × 75mm substrates continuously. Mass spectrometer data on the composition of the residual gases present during various steps of the pumping process and the outgassing characteristics of evaporation source (BeO crucible) are given.