Experimental Laboratory Exercises

Making electrical measurements in a SEM

Electronic devices tend to have sizes between a few nanometers to a few microns. To fully understand the operation of these devices it is often necessary to measure the current distribution and the electrostatic potential on a scale smaller than the device itself. This makes it necessary to operate the devices inside some kind of microscope that can resolve these small length scales. A Scanning Electron Microscope (SEM) typically has a resolution of about 10 nm and makes images fairly quickly. To make electrical measurements, microomanipulators have been installed inside the SEM. These micromanipulators are small robotic arms that can be controlled with a resolution of a few tens of nanometers. The micromanipulators hold sharp metal tips like those used in a scanning tunneling microscope to make contact to the devices.

• Qing Chen, Sheng Wang and Lian-Mao Peng, Establishing Ohmic contacts for in situ current–voltage characteristic measurements on a carbon nanotube inside the scanning electron microscope, Nanotechnology 17 (2006) 1087–1098