Electrically-functionalised nanoindenter dedicated to local capacitive measurements: Experimental set-up and data-processing procedure for quantitative analysis

摘要

In this work, we report the experimental development and the application of a new characterisation tool combining mechanical testing and dielectric characterisation. The experimental set-up is essentially a nanoindentation head functionalised for capacitive measurements. First the experimental procedure for the characterisation of dielectric thin films is given: detailed set-up description, procedure for the capacitance-vs-voltage (C-V) measurements, stray capacitance. Secondly, a complete data-processing method is proposed to perform the quantitative analysis of capacitance data. To this end, a fully analytical model has been developed, able to relate the C-V curves to the system characteristics (set-up geometry and specimen properties) without any fitting parameter. Finally dielectric films with different thicknesses and relative permittivities have been tested to validate both the characterisation tool and the data-processing method. The analytical model has been used to predict the permittivity of each dielectric thin film. The extracted data have been compared to data obtained from a calibrated macro-scale technique and showed remarkable agreement. One of the strengths of the data-processing method is to eliminate the stray capacitance which usually disturbs local capacitance measurements. Even though the effect of mechanical load is not investigated in the present study, the experimental proof-of-principle is shown and the data-processing method is validated. This work opens prospects for local and quantitative dielectric characterisations under mechanical loads. It should also fill a gap between quantitative characterisations at macro-scales and spatially highly-resolved characterisations at nano-scale. (C) 2019 Elsevier B.V. All rights reserved.