  A multiple-tip ultra-high vacuum (UHV) scanning tunneling microscope (MT-STM)
with a scanning electron microscope (SEM) for imaging and molecular-beam
epitaxy growth capabilities has been developed. This instrument (nanoworkbench)
is used to perform four-point probe conductivity measurements at micrometer
spatial dimension. The system is composed of four chambers, the multiple-tip
STM/SEM chamber, a surface analysis and preparation chamber, a molecular-beam
epitaxy chamber and a load-lock chamber for fast transfer of samples and
probes. The four chambers are interconnected by a unique transfer system based
on a sample box with integrated heating and temperature-measuring capabilities.
We demonstrate the operation and the performance of the nanoworkbench with STM
imaging on graphite and with four-point-probe conductivity measurements on a
silicon-on-insulator (SOI) crystal. The creation of a local FET, whose
dimension and localization are respectively determined by the spacing between
the probes and their position on the SOI surface, is demonstrated.
