SCANNING FORCE MICROSCOPY OF SEMICONDUCTOR-MATERIALS AND DEVICES

Tip microscopy techniques have become very widely spread methods of scanning imaging of microstructures or nanostructures in almost any material problem. This applies both to scanning tunnelling microscopy and to scanning force microscopy (SFM). By SFM a specimen can be examined without the necessity of extensive sample preparation, allowing fast response of the microscopist to technological problems. Whereas SFM in its usual axial force mode is mainly used to image topography of the sampled surface or the distribution of surface atoms, newly developed techniques deliver more relevant information with respect to semiconductor properties. Various modifications may be carried out easily to determine electrical or electronical microfeatures. In this sense, imaging of internal potential distributions or of specimen internal waveforms can be achieved by determining electrostatically acting forces; using a metallized tip with an appropriate work function, local conductivity measurements can be carried out. The correlation of such electrical or electronical properties to the sample topography can be done by simultaneous recording of its topography. Here it has become obvious that lateral force imaging gives more detailed information than the more common axial mode.