Nanometer scale patterning by scanning tunelling microscope assisted chemical vapour deposition

Single electron devices are of great interest for their possible replacement of transistors in memories. The key to the preparation of these components is the production of low capacitance dots, which requires a lithography step at nanometric scale. Direct patterning of metallic features at nanometric scale is possible by local decomposition of gaseous molecules under a scanning tunneling microscope (STM) tip, by application of a voltage of a few volts on the sample (STM assisted chemical vapour deposition). The gaseous molecules are dissociated by the high electric field (about 107 V/cm) within the tip–sample gap. Rhodium lines and dots have been deposited on gold or silicon surfaces by decomposition of [Rh(PF3)2Cl]2. The influence of the sample voltage was studied and the resolution limit of the technique was investigated.