A UHV STM for in situ characterization of MBE/CVD growth on 4-inch wafers

A UHV STM has been designed for combination with a multipurpose MBE/UHV-CVD system. A small UHV chamber containing the STM is attached to the load lock of the MBE chamber for sample transfer. For high resolution measurements, the STM chamber is detached from the MBE/CVD machine to reduce the noise level and to avoid the transmission of vibrations. Vibration isolation is provided by laminar flow isolators carrying the whole chamber as well as by a spring/eddy current assembly damping the sample holder and the STM. Emphasis is put on the suppression of eigenmodes of the 4-inch wafer. The STM itself, based on the 'Beetle'-microscope with an inchworm motor for tip approach, is placed directly on the wafer. The area which can be investigated corresponds to similar to 40 cm(2). The instrument performance is demonstrated for Si(111) and Si(001) surfaces.