Anasys Instruments announce the release of a new Scanning Thermal Microscopy (SThM) accessory that enables a number of commercially available AFMs to generate nanoscale thermal images while simultaneously obtaining contact mode images of the topography. The accessory includes hardware, software and probes as well as a cantilever holder designed for the specific SPM of the user. SThM capability is a subset of the full suite of nano-TA2 methods available and can be easily upgraded to provide localised thermal analysis measurements should a user’s applications required more advanced capability. The SThM allows the user to image nanoscale variations in surface temperature with a relative accuracy of 0.1ºC.
The SThM mode works by replacing the standard contact mode AFM probe with a specialized probe that incorporates a resistor near the apex of the probe tip. This resistor is incorporated into a Wheatstone bridge circuit which allows the system to monitor the resistance. The resistance correlates with the temperature at the end of the probe, which can be used to both monitor the temperature of a sample as well as map out thermal conductivity of the sample in a qualitative manner. Sample temperatures are typically measured on active device structures such as magnetic recording heads, laser diodes or an electrical circuit. Conversely, thermal conductivity is more typically measured on composite samples. In this measurement, more voltage will be applied to the probe increasing it further above room temperature. The thermal conductivity of the sample will affect the temperature of the probe by draining more or less heat away from the tip.
Anasys Instruments provides batch fabricated thermal probes which provide better than 100 nm resolution for both the topography and thermal images. The cantilever is made of SiO2 with a thin metal wire deposited so that the highest resistance portion of the wire is near the apex of the tip. These tips are pre-mounted on supports and electrically connected for minimal handling and ease of use. Anasys Instruments has developed specialized cantilever holders for all of the major SPM manufacturers.