Investigation of the Accuracy and Spatial Resolution of Scanning Thermal Microscopy (SThM) Technique
Scanning Thermal Microscopy (SThM) employs a thermocouple as the scanning sensor to capture thermal images with sub-micron spatial resolution. After nearly two decades of research and development in this area, many outstanding issues/questions related to the accuracy and resolution of SThM technique has remained either unanswered or at best ambiguously defined. The present work uses numerical simulation for heat conduction in a combined SThM probe and device to obtain temperature distributions in various heated nanostructures. The limits of accuracy and spatial resolution of the SThM technique for heated metal bridges are estimated using a probe with 100 nm thermocouple junction as the temperature sensor. It is concluded mat large errors in temperature measurements should be expected for small devices that are fabricated on poor thermal conductivity substrates. There is no clear and unique definition for the spatial resolution of the SThM technique as it may change for different device configuration and substrates. It appears that the finite dimensions of the probe and contact area impose a limit on the spatial resolution of the SThM, which is strongly influenced by temperature gradients across the device under test.