Field Ion-Scanning Tunneling Microscope Equipped with Molecular Beam Epitaxy and Its Application to Study Semiconductor Surface Structure

We have developed a new combined system of a field-ion scanning tunneling microscope (FI-STM) and a molecular beam epitaxy (MBE) growth chamber equipped with six Knudsen-cells and reflection high energy electron diffraction (RHEED). This system allows us to observe compound semiconductor surfaces such as GaAs while keeping their surfaces clean. In this paper, this system was applied to GaAs(100) and Si(110) surfaces. A GaAs sample was heated up to 550°C and a GaAs thin epitaxial film was grown by MBE. 2×, 4× structures were observed by RHEED and the sample was moved to the FI-STM chamber where STM images of 2×4 reconstructed GaAs(100) surfaces were obtained. Besides the observation of GaAs, FI-STM was also applied to the Si(110) surface. We have studied the change of the Si(110) surface structures at different conditions of heating and cooling.