High resolution vacuum scanning thermal microscopy of HfO2 and SiO2

We present scanning thermal microscopy (SThM) measurements on a sample consisting of regions of 3nm thick HfO2 film and 2nm thick SiO2 on a silicon substrate. The experiments were preformed in high vacuum conditions using microfabricated silicon cantilevers with sharp heatable tips, facilitating the unprecedented achievement of a lateral SThM image resolution of 25nm. In addition, the heat transfer through the tip to the sample was investigated using approach curves and used to determine the thermal conductivity of the 3nm thick HfO2 layer.