MANUFACTURE OF MICROMECHANICAL SCANNING TUNNELING MICROSCOPES FOR OBSERVATION OF THE TIP APEX IN A TRANSMISSION ELECTRON-MICROSCOPE

A micromechanical scanning tunnelling microscope (mu-STM) is fabricated on a 2.5 mm square chip by an advanced very-large-scale integrated circuit technology with a minimum dimension of 0.6 mu m and alignment accuracy of 0.1 mu m. The mu-STM is designed to fit into a transmission electron microscope (TEM) for direct observation of the tip apex. The electrostatic actuators and springs are designed to produce a large force that is linear with applied voltage to overcome the forces between the tip and sample. The mu-STMs have been operated and shown to work reliably, even during observation of the tip apex in a TEM machine. This demonstrates the possibility of analysing the tunnelling gap physics and material transport mechanism at the tip apex using a TEM.