In Situ Fabrication, Manipulation, and Mechanical Characterization of Free-Standing Silica Thin Films Using Focused Ion Beam Scanning Electron Microscopy

Determination of mechanical properties of (silica) thin films is important for the development of new applications. However, a versatile approach for small-scale sample fabrication and in situ mechanical testing of these materials is currently lacking which can overcome the existing difficulties in conventional testing approaches. Here, it is shown that by combining focused ion beam scanning electron microscopy (FIB-SEM) with micromanipulators free-standing silica beams of the desired dimensions can be fabricated. Using in situ bending tests on such beams inside the SEM and finite element method simulations, the Young's modulus of thin-film silica and the effects of gallium ion beam radiation on Young's modulus are determined. Furthermore, the effects of controlled relative humidity on the mechanical behavior of silica beams are investigated. The demonstrated FIB-SEM approach can be extended to other materials and preparation conditions to measure, model, and optimize mechanical properties of thin films for a wide range of (coating) applications.