Quantitative Thermal Microscopy Measurement with Thermal Probe Driven by dc+ac Current

• Published in: International journal of thermophysics Vol. 37; no. 7; pp. 1 - 17
• Main Authors: Bodzenta, Jerzy, Juszczyk, Justyna, Kaźmierczak-Bałata, Anna, Firek, Piotr, Fleming, Austin, Chirtoc, Mihai
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.07.2016
• Subjects: Classical Mechanics; Condensed Matter Physics; Heat transfer; Icppp 18; ICPPP-18: Selected Papers of the 18th International Conference on Photoacoustic and Photothermal Phenomena; Industrial Chemistry/Chemical Engineering; Measurement methods; Physical Chemistry; Physics; Physics and Astronomy; Spatial resolution; Substrates; Thermal conductivity; Thermal properties; Thin films; Finite element method; Numerical analysis; Thin layers; Scanning thermal microscopy; Thermal conductivity measurement
• ISSN: 0195-928X; 1572-9567
• DOI: 10.1007/s10765-016-2080-y

Quantitative thermal measurements with spatial resolution allowing the examination of objects of submicron dimensions are still a challenging task. The quantity of methods providing spatial resolution better than 100 nm is very limited. One of them is scanning thermal microscopy (SThM). This method is a variant of atomic force microscopy which uses a probe equipped with a temperature sensor near the apex. Depending on the sensor current, either the temperature or the thermal conductivity distribution at the sample surface can be measured. However, like all microscopy methods, the SThM gives only qualitative information. Quantitative measuring methods using SThM equipment are still under development. In this paper, a method based on simultaneous registration of the static and the dynamic electrical resistances of the probe driven by the sum of dc and ac currents, and examples of its applications are described. Special attention is paid to the investigation of thin films deposited on thick substrates. The influence of substrate thermal properties on the measured signal and its dependence on thin film thermal conductivity and film thickness are analyzed. It is shown that in the case where layer thicknesses are comparable or smaller than the probe–sample contact diameter, a correction procedure is required to obtain actual thermal conductivity of the layer. Experimental results obtained for thin SiO 2 and BaTiO 3 layers with thicknesses in the range from 11 nm to 100 nm are correctly confirmed with this approach.