Determination of Density and Young's Modulus of Atomic Layer Deposited Thin Films by Resonant Frequency Measurements of Optically Excited Nanocantilevers

Abstract

We report on a methodology for simultaneous determination of the Young's modulus and density of ultrathin films from a resonance experiment. The approach is based on an interferrometric detection of the in-plane and out-of-plane resonant responses of an optically excited single crystal Si nano cantilever prior and after Atomic Layer Deposition (ALD) of a thin film. The frequencies shifts were measured at the same structure reducing sensitivity to scattering in geometric parameters and clamping compliances. Experimental results obtained for A1203 (alumina) and HfO2 (hafnia) were consistent with the model predictions and the data available in literature.

A Simple Extraction Method of Young’s Modulus for Multilayer Films in MEMS Applications

“…Material mechanical parameters, such as Young’s modulus, residual stress, and so on, not only have great effect on the functions of MEMS (Micro-Electro-Mechanical System) devices, but also have great influence on yield, service life, and the work reliability of MEMS devices. However, it is a challenging task to detect and measure the mechanical properties of thin films and membrane structures for MEMS applications [ 1 , 2 , 3 , 4 ]. In surface micromachining technology, with the same membrane structures, different processes will lead to different material properties.…”