Fabrication of micromechanical tunneling probes and actuators on a siliconchip

Simultaneous visual control of tip position is indispensable for in-situ ob servation of nanoscopic phenomena at the tunneling gap. In this paper we pr opose a one-chip tunneling control device, which is small enough to load on a standard sample holder of the transmission electron microscope (TEM). Tu nneling probes and micro actuators have been successfully integrated on a 2 .4 x 2.4-mm(2)-chip by silicon micromachining technique. A pair of sharp si licon tips is obtained by the combination of stress-induced oxidation and s elective etching of silicon oxide. Typical dimensions of the tips are 10 nm in radius and I mum in length with a 200-nm-initial gap. An electrostatica lly operated comb-drive actuator is used to close the gap with a voltage ar ound 100 V. The tunneling tips are suspended over a through hole in the bas e substrate, and the tunneling gap can be observed by TEM. We found that cl ear images could be obtained without distortion or shift due to the driving voltage applied to the integrated actuator.