A general method for calibration of active scanning thermal probes

Abstract

Scanning Thermal Microscopy (SThM) is a scanning probe technique aimed at quantitative characterization of local thermal properties at the length scale down to tens of nanometers. With many probe designs and approaches to interpretation of probe responses, there is a need for a universal framework, which would allow probe calibration and comparison of probe performance. Here, we have developed a calibration framework based on an abstracted, formal, probe model for active SThM probes. The calibration can be accomplished through measurements with two or three calibration samples. Requirements to calibration samples are described with examples of structures of suitable samples identified in published literature. A link to a published experimental work indirectly verifying the proposed procedure is provided. The calibration does not require knowledge of internal probe properties and yields a small and universal set of parameters that can be used to quantify thermal resistance presented to the probe by samples as well as to characterize active-mode SThM probes of any type and at any measurement frequency. We have illustrated how the probe calibration parameters can be used to guide probe design. We have also analyzed when the calibration approach can be used directly to measure thermal conductivity of unknown samples.