Connection of a Scanning Tunneling Microscope with a Molecular Beam Epitaxy Chamber and Analysis of the Vibration Isolation System

A scanning tunneling microscope has been connected to a high vibrating commercial Molecular Beam Epitaxy (MBE) system, in order to study InGaAs layers grown on InP. An original and well efficient vibration isolation system has been designed and built: the microscope support, stiffly linked to a vibration free inert mass has been connected through a highly flexible bellow to the MBE system. The main characteristic of this design is a low transmission factor at low frequencies. A detailed analysis of this system has been made to determine the main parameters of the transfer function and optimize the performances. Crucial problems concern the bellow which for efficient damping of the eigen mode vibrations has to be adapted, and the sample weight which has to be lowered. The efficiency of this vibration isolation system has been demonstrated by high resolution imaging of the graphite surface and of the surface of an InGaAs buffer layer epitaxially grown on an InP (100) substrate.