Experimental Study Mechanical Stresses and Strength in Multilayer PECVD SiO2

Abstract

The problem for researchers and developers is inaccurate data on the mechanical strength of thin-film materials due to size effects during the transition from macro to micro levels of thicknesses of the studied layers. The objective of this work is to experimentally determine the mechanical stresses and mechanical strength of SiO2 thin-film membranes obtained by the layer-by-layer deposition. To achieve this goal, we used analytical equipment (ellipsometer, SEM, optical profiler), computing equipment (calculations in MATLAB), and technological (system for the deposition of thin films). The mechanical strength of SiO2 is experimentally determined by the bulge method. The value of mechanical stresses varies from 188 to 26.7 MPa with an increasing thickness of SiO2 from 226 to 2017 nm. The determined value of the mechanical strength of silicon oxide is 1.84 GPa for a thickness of 1.5 microns and 1.27 GPa for a thickness of 2 microns. The layer-by-layer deposition of a thin film of silicon oxide by the PECVD method can reduce the value of mechanical stresses. The measured values of mechanical strength correlate well with the results of other studies.