Methodological correlation of finite element models to nanoindentation measurements on Si (100)

A viable approach to obtain mechanical properties such as Young’s modulus and hardness, is testing on a nanoindentation device. Such an experimental procedure can, however, be time-consuming and expensive. Finite element analysis (FEA) can be employed to minimize the number of required measurements, i.e., to obtain numerically the load vs. indentation depth curves for varying input parameters, hence extracting the resulting elasto-plastic material properties. A methodological approach is used in this work to correlate the responses obtained via FEA to nanoindentation experimental data. A (100)-oriented single crystal silicon wafer is used as a testing sample. Numerical simulations are performed by employing a bilinear elasto-plastic material model. A sensitivity analysis of the characteristic parameters of the material model is then conducted on the numerically obtained load vs. displacement curves. The proposed methodology enables replicating the experimental curves with estimated errors lower than 1 % and 15 % for Young’s modulus and hardness, respectively. The performed analyses allow establishing also that, when evaluating numerically hardness, the tip radius and shape significantly affect the accuracy of the results, especially for lower indentation depths.