Development of scanning micro-evaporator for the study of SiGeC

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In recent years deivice sizes hve been decreased to nano-meter scale dimensions, and mesoscopic properties of electrons have come to be important. In these devices, it is certainly important to controle the electron scattering at the interfaces. The defects at the interface interfare the phase of the electorons and afect the electron transport in the devices. In this research we have aimed to develop a miniaturized evaporator to make a well defined nano-stuructures on atomically flat surfaces, to see any effect of the electron transport from the nano-structures.We designed a specific specimen holder for nano-structure fablication. The specimen holder has a miniaturized STM,on top of which an evaporant can be attached, and a specimen faced to the STM tip. The specimen holder is used for the ultra-high vacuum electron microscope (UHV-EM) to observe any nano-structures formed on the specimen surface.We used a silicon crystal as a substrate and a tungsten tip as an evaporant. When the tip was approached to the sample surface so close as 1 nm, and field of a few eV was applied between the tip and the sample, we found that a tungsten droplet was desorped from the tip side to be deposited on the substarte. This field evaporation technique for a micro-area deposition to produce nano-wires on the silicon surface was found to be not enough to wires of uniform thickness, because of poor controle of the field strength on the tungsten tip.Anyway, we have succeeded to approach the evaporant to a sumple surface as close as a few nm, the approaching process being observed directly by electron microscopy. The scanning capability of the evaporant by STM allow us to form nano-structures, which are also observable by reflection electron microscopy.The present reseach showed a possibility of nano-scale fablication on an atomically flat and clean surface.