CRYSTAL-GROWTH TECHNOLOGY FOR ULTRAHIGH-SPEED DEVICES

Epitaxial growth techniques under Ultrahigh Vacuum (UHV) conditions have been developed for ultrahigh-speed-device applications. UHV technology is very useful not only for the growth of pure III-V compound semiconductors but also for the diagnosis of residual gases, crystal surface and chemical reactions. In solid source Molecular Beam Epitaxy (MBE), Reflection High-Energy Electron Diffraction (RHEED) technique monitors layer-by-layer growth in situ, and provides submonolayer controllability. In Metalorganic MBE (MOMBE), p- and n-type selective epitaxial growth has been developed using direct chemical reactions on substrate surface. Furthermore, a surface cleaning technique has been studied using a high vacuum system, where MBE growth and gas etching can be operated sequentially without air exposure. This paper introduces these activities and discusses trends of UHV technology for ultrahigh-speed devices.