Library Subscription: Guest

ISSN Online: 2377-424X

International Heat Transfer Conference 12
August, 18-23, 2002, Grenoble, France

Calibration of scanning thermal microscopes for conductivity measurements

Get access (open in a dialog) DOI: 10.1615/IHTC12.4140
6 pages

Abstract

Thermal mapping with nanoscale spatial resolution requires the use of contact probe techniques. Among them, the atomic force microscope (AFM) based measurements provide the highest resolution ranging from a few to several dozens of nanometers. We use an AFM probe consisting of a hot platinum wire to measure thermal conductivity. While in contact with the sample surface, the electrical current I injected into the probe is controlled so that electric resistance or wire temperature is maintained by Joule effect. The current variation is directly related to the heat flow lost towards the sample. Traditional calibration is carried out by relating the thermal conductivity of a set of samples to the measured current I. A linear dependence is assumed and a constant tip-sample contact conductance is supposed. However, none of those conditions can reasonably be accepted. We provide analytical and numerical thermal modelling of tip and sample to show the impact of the different heat fluxes on a basic conductivity calibration. A simple expression is finally established to calculate the thermal conductivity from the input current I.