The combined UHV AFM/STM is a versatile scanning probe microscope, designed for measurements at room temperature. It combines STM and AFM measurement modes including contact mode AFM with simultaneous lateral force (friction) detection and non-contact mode AFM in a single instrument. Since 1993 more than 200 instruments have been delivered and installed successfully around the world. With this instrument design atomic resolution on a true insulator (Al2O3(0001)) has been achieved in non contact AFM mode [1] for the first time.
[1] C. Barth et.al. Nature 414, 54 (2001)

The AFM measurement is based on optical beam deflection in this setup. This detection method offers unsurpassed force sensitivity and allows high resolution imaging in contact mode with very low forces down to the 10^-11 N range. Two ball mirror-motors are used to align the light beam onto the cantilever and to position the reflected beam on a position sensitive quadrant cell detector (PSD). The PSD allows simultaneous detection of normal and lateral forces. The instrument accepts both STM tips and all commercially available cantilevers.

Easy UHV system integration!
The UHV AFM/STM is housed in its own, dedicated UHV chamber which can either be mounted onto a standard Omicron system (MULTIPROBE…) or “bolted-on” to an existing vacuum system. In this case the wobble stick enables the sample transfer from the main vacuum system to the UHV AFM/STM. Instead of directly mounting the bolt-on SPM chamber to an existing system, Omicron also offers specifically designed small sub-systems. These operate as stand-alone systems and can be connected via a sample transfer mechanism to any existing system.

An easy-to-use, pincer-grip wobble stick is used for the fast transfer between the main system manipulator, the sample/tip storage carousel, and the UHV AFM/STM. Tips/cantilevers are transferred using tip carrier plates.

Introduced as part of the first commercial UHV STM in the 1980’s, the OMICRON eddy current vibration isolation system defined a milestone in UHV SPM technology. The proven design allows high resolution Scanning Tunnelling Microscopy operation even in non-ideal conditions for more than 25 years.