Experimental work this past year was primarily directed toward enhancing the growth and characterization capabilities of the PI's laboratory. Significant improvements were completed on the MBE system and the in-situ ellipsometry apparatus was demonstrated in a bread board setup. Theoretical work consisted of preliminary Monte-Carlo investigation of the MBE growth III-V compounds. Extensive progress was made on modeling the phase separation occurring during growth of Al(x)Ga(1-x)As on (110) GaAs. A mismatch induced, strain dependent exchange reaction between Al and Ga was shown to give long period variations in the Al concentration. The specific predictions of the theory will be tested in a collaborative effort with JPL.

From time of the inception of this work, it became clear at a relatively early stage that the USC MBE facility required major effort and investment to be able to grow reliable samples. In an effort to achieve this aim, the principal investigator was forced to take responsibility of the MBE growth as well - a situation not originally anticipated. Accordingly, major effort was spent making the USC MBE machine operational and putting in place basic support facilities (such as substrate cleaning and preparation). The situation with regard to the MBE machine thus, unfortunately, deprived us of appropriate GaAs/A1 Ga1-xAs samples to be able to proceed with certain experiments. We did, however, grow a few GaAs/A1x Ga1-xAs/GaAs tunnelling structures had them fabricated into actual tunnel structures, and carried ou Fowler-Norheim resonance tunnelling experiments at JPL. The results indicated that the interfacial quality of these structures were rather poor.

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This program undertakes experimental and theoretical investigation of the role of growth kinetics and mechanism(s) in molecular beam epitaxial growth of III-V semiconductors and its possible control via laser excitation to effect metastable structures and phases. The experimental work on laser induced MBE growth is collaboratively carried out. Specifically, progress is reported on (i) Monte-Carlo computer simulations of MBE growth and predictions of the dynamics of reflection-high-energy-electron-diffraction (RHEED) intensities (ii) a theory of laser--induced-desorption (iii) Experimental studies of the RHEED intensity dynamics for GaAs/InxGa1-xAs(100) MBE growth (iv) the first realization of GaAs/InAs strained layer structures (with 7.4% lattice mismatch) and transmission electron microscopy studies showing high quality interfaces, and (v) establishment of a facility for magneto-absorption studies.

Epitaxial Silicon Technology is a single-volume, in-depth review of all the silicon epitaxial growth techniques. This technology is being extended to the growth of epitaxial layers on insulating substrates by means of a variety of lateral seeding approaches. This book is divided into five chapters, and the opening chapter describes the growth of silicon layers by vapor-phase epitaxy, considering both atmospheric and low-pressure growth. The second chapter discusses molecular-beam epitaxial growth of silicon, providing a unique ability to grow very thin layers with precisely controlled doping characteristics. The third chapter introduces the silicon liquid-phase epitaxy, in which the growth of silicon layers arose from a need to decrease the growth temperature and to suppress autodoping. The fourth chapter addresses the growth of silicon on sapphire for improving the radiation hardness of CMOS integrated circuits. The fifth chapter deals with the advances in the application of silicon epitaxial growth. This chapter also discusses the formation of epitaxial layers of silicon on insulators, such as silicon dioxide, which do not provide a natural single crystal surface for growth. Each chapter begins with a discussion on the fundamental transport mechanisms and the kinetics governing the growth rate, followed by a description of the electrical properties that can be achieved in the layers and the restrictions imposed by the growth technique upon the control over its electrical characteristics. Each chapter concludes with a discussion on the applications of the particular growth technique. This reference material will be useful for process technologists and engineers who may need to apply epitaxial growth for device fabrication.