A UHV-compatible thin-film stress-measuring apparatus based on the cantilever beam principle

Abstract

A stress-measuring apparatus based on the cantilever beam principle is described that can be used to determine the internal stress of thin films continuously during and after their deposition. The displacement of the free end of the cantilever beam−which is proportional to the film stress−is determined with high sensitivity and long time stability using a differential capacitance method in combination with phase-sensitive detection. The entire apparatus is fully compatible with UHV requirements and includes provisions for heating and cooling the substrate. The reproducible performance of the stress-measuring apparatus is demonstrated with silver films deposited onto MgF2-coated substrates.