As the dimensions of electronic devices and components continue to decrease the surfaces and interfaces between different materials becomes more and more a critical feature of the device. Often dominating its operation and function.

To measure surface properties a whole new class of microscopes have been developed, called Scanned Probe Microscopes.

Each type is very different in how they operate but all use some form of ‘probe’, usually a sharp tip of some kind, which is brought very close, or even into contact, with the surface. The probe is then scanned over the surface, line by line; information on each data point is sent on a computer so that eventually an image of the surface can be obtained on the computer screen.

NPL has many different types of scanned probe microscopes, some commercial instruments and some, state-of-the-art ones that we have developed ourselves. These microscopes are able to measure a very wide range of properties of the surfaces. The properties measured may be magnetic, electrical conductance, thermal conductance, capacitance, atomic-forces, spin-polarised conductance and many others, although no one system can measure every property; that is why so many different types are needed.

All are able to show the surface in very high detail, some even down to the atomic scale!

Two very specialised instruments developed by NPL are a variable temperature STM and a Cryo AFM