MRI: Development of a Surface Scattering System for Real-time X-ray Studies of Growth and Processing

Trustees Of Boston University, Boston

Investigators

Abstract

This award funds the development of a system for the in-situ synchrotron x-ray study of thin film growth with molecular beam epitaxy (MBE) and of surface modification with plasma processing. The system will permit extensive x-ray access to the sample and incorporate standard characterization tools (e.g. RHEED) to better correlate the synchrotron results with in-house studies. In the area of film growth, particular attention is paid to surface structure during the MBE growth of III-V nitride films, both GaN and Ga-Al-In nitride alloys. Among other issues, research will focus on buffer layer formation and atomic ordering/phase separation in the alloy systems. Investigations of surface structure during plasma processing will initially focus on silicon, since it has been widely studied with complementary methods. Future experiments will be directed at processing of compound semiconductor surfaces, such as those of the arsenides and nitrides. Students trained with the system will be exposed to a broad range of materials issues ranging from basic surface structure research to understanding how surface structure can effect device performance. They will be well prepared to bring their experience and new insights to industry and academia following graduation. This award funds the development of a surface scattering system for real-time x-ray studies of growth and processing. The system will enable the fundamental study of two processes that are vital for the semiconductor industry. These are, first, Molecular Beam Epitaxy, which allows the highly controlled growth of thin films a single atomic layer at a time, and, second, the modification of surfaces with energetic particles in a set of processes that is known collectively as "plasma processing". Using a very intense beam of x-rays from a synchrotron source, the atomic structure of surfaces will be investigated as these technologically important processes are occurring. The basic understanding gained from these experiments may eventually lead to methods for growing new high quality materials for the optoelectronics and high power industries and to better methods of etching and passivating semiconductor surfaces throughout the electronics industry. In addition, this equipment will provide a unique resource to train students in these rapidly developing interdisciplinary areas that cut across traditional boundaries of physics, materials science and electrical engineering.