Jan Martinek

Large area high-speed metrology SPM system

We present a large area high-speed measuring system capable of rapidly generating nanometre resolution scanning probe microscopy data over mm(2) regions. The system combines a slow moving but accurate large area XYZ scanner with a very fast but less accurate small area XY scanner. This arrangement enables very large areas to be scanned by stitching together the small, rapidly acquired, images from the fast XY scanner while simultaneously moving the slow XYZ scanner across the region of interest. In order to successfully merge the image sequences together two software approaches for calibrating the data from the fast scanner are described. The first utilizes the low uncertainty interferometric sensors of the XYZ scanner while the second implements a genetic algorithm with multiple parameter fitting during the data merging step of the image stitching process. The basic uncertainty components related to these high-speed measurements are also discussed. Both techniques are shown to successfully enable high-resolution, large area images to be generated at least an order of magnitude faster than with a conventional atomic force microscope.

Methods for topography artifacts compensation in scanning thermal microscopy

Thermal conductivity contrast images in scanning thermal microscopy (SThM) are often distorted by artifacts related to local sample topography. This is pronounced on samples with sharp topographic features, on rough samples and while using larger probes, for example, Wollaston wire-based probes. The topography artifacts can be so high that they can even obscure local thermal conductivity variations influencing the measured signal. Three methods for numerically estimating and compensating for topographic artifacts are compared in this paper: a simple approach based on local sample geometry at the probe apex vicinity, a neural network analysis and 3D finite element modeling of the probe-sample interaction. A local topography and an estimated probe shape are used as source data for the calculation in all these techniques; the result is a map of false conductivity contrast signals generated only by sample topography. This map can be then used to remove the topography artifacts from measured data or to estimate the uncertainty of conductivity measurements using SThM. The accuracy of the results and the computational demands of the presented methods are discussed.

Thermal conductivity analysis of delaminated thin films by scanning thermal microscopy

Scanning thermal microscopy (SThM) is a scanning probe microscopy technique for mapping temperature and thermal properties of solid surfaces with very high resolution. It has been used for the determination of various thermophysical properties in the past and it delivers better lateral resolution than any other thermal technique. Absolute determination of thermal conductivity using SThM, however, is still problematic due to the complex nature of the heat exchange between the probe and sample. In this paper we present a method for thin film thermal conductivity determination based on the use of thin film defects—delaminations. We show that, using a combination of bonded and debonded film measurements together with numerical analysis, we can use a single SThM measurement to determine the isotropic thermal conductivity of the film, without a priori knowledge of probe–sample junction properties.