Large Area And High Aspect Ratio Scanning Tunneling Microscope Technology

Currently, scanning probe measuring system is the best tool that has the capability of direct measurement of surface topography. Scanning tunneling microscope (STM) has been used widely in the surface topography for the conductive workpieces that were usually manufactured or fabricated by ultra-precision machining or MEMS technology. However, the small measuring area and low aspect ratio capability precluded it from being widely used in ultra-precision metrology. Therefore, development of novel STM system with characterizations of large area and high aspect ratio capability is necessary and urgent.In order to improve high aspect ratio measuring capability, the technology that can produce high aspect ratio 99.999% pure tungsten STM probe was fulfilled. Typically, the newly fabricated tips with exponential curve, the apex radius less than 50 nm, length-radius-ratio 50:1 were made stably. In order to enlarge the measuring range, a new scanning system was designed, in which high-speed, high-precision micro-stages were used to achieve X-Y plane scanner with large scanning area.The prototype STM has the capabilities of large area and high aspect ratio was designed and built. It achieved a breakthrough in measuring range and high aspect ratio measurement. The stability and overall performance were improved through the testing and optimization of subsystems. The surface topography of the samples was obtained through testing and analyzing various micro-/nano- structures with complicated topography, which verified the capability of the new STM system.Finally, the summaries of this new STM and its potential application were given for the purpose of further development of STM technology.