Frequency domain measurements of thermal properties using 3omega-Scanning Thermal Microscope in a vacuum environment

TL;DR

This paper presents a detailed methodology combining probe characterization and finite element modeling to accurately measure thermal properties at the nanoscale using a 3omega-Scanning Thermal Microscope in vacuum, including thermal interface resistances.

Contribution

It introduces a two-step approach for in-operando 3omega measurements that enhances the accuracy of thermal property characterization at the nanoscale.

Findings

Accurate measurement of thermal interface resistances for silicon, silica, and gold.

Insights into the sensitivity of the 3omega-SThM technique to interface resistance.

Method enables quantitative thermal conductivity measurements.

Abstract

Material thermal properties characterization at nanoscales remains a challenge even if progresses were done in developing specific characterization techniques like the Scanning Thermal Microscopy (SThM). In the present work, we propose a detailed procedure based on the combined use of a SThM probe characterization and its Finite Element Modeling (FEM) to recover in-operando 3omega measurements achieved under high vacuum. This approach is based on a two-step methodology: (i) a fine description of the probe s electrical and frequency behaviors in out of contact mode to determine intrinsic parameters of the SThM tip, (b) a minimization of the free parameter of our model, i.e. the contact thermal resistance, by comparing 3omega measurements to our simulations of the probe operating in contact mode. Such an approach allows us to accurately measure thermal interface resistances of the probe as a function of the strength applied between the tip and the surface for three different materials (silicon, silica and gold). In addition, FEM modeling provides insights about the 3omega-SThM technique sensitivity, as a function of probe / sample interface resistance to measure material thermal conductivity, paving the way to quantitative SThM measurements.