STM studies:: spatial resolution limits to fit observations in nanotechnology

Atomically resolved Scanning Tunneling Microscopy (STM) images are nowadays currently obtained on flat surfaces without any special STM tip preparation. On the contrary, imaging of three-dimensional nanometer-scale objects exhibiting very much inclined facets, requires the use of STM tips with an appropriate geometry. The tip shape has to be controlled over the whole length that corresponds to the height of the object to be imaged. The cone angle of the tip has to be smaller than the tilt angle of the imaged facets. These criteria are also required when STM tips are used for patterning of nanometer-scale dots. In this paper, we will present the spatial resolution limits determined for these tips on different calibration gratings as well as first results obtained on nanometer scale patterning. (C) 2000 Elsevier Science B.V. All rights reserved.