Coated Tips for Scanning Thermal Microscopy

This paper presents a unique solution to the inaccuracies produced when thermally scanning various micro and nano systems with thermistor tip scanning thermal microscopy (SThM). Under dc measurement conditions, thermistor tip heating induces perturbations in the measured system that change with sample properties like material and geometry. As a result, normal SThM scans are affected by errors that make it difficult to interpret the 2D-temperature scans of such systems. By coating the SThM tips with a thermally resistive material (100nm of Si₃N₄) we demonstrate that the temperature dependence on sample material and geometry can be minimized and the tip heating problem can be mitigated to that of a constant temperature offset problem. Included are the first images of coated scanning thermal microscopy (C-SThM) as well as a lumped model that describes the basis of the improvement seen in the thermal images.