I. Heteroepitaxy on Si. II. Ion implantation in Si and heterostructures

Citation

Bai, Gang (1991) I. Heteroepitaxy on Si. II. Ion implantation in Si and heterostructures. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/v8kr-gm23. https://resolver.caltech.edu/CaltechETD:etd-06282007-105319

Abstract

The themes of this thesis, heteroepitaxy and ion implantation, are two areas that have been very actively researched in the last two decades.

Heterostructures made of III-V compound semiconductors by MBE and OMVPE have been used extensively in the fabrication of optoelectronics devices such as high-speed transistors and semiconductor lasers. Heterostructures on Si, which is the focus of part I of this thesis, have the advantage of compatibility with Si-based VLSI and promise to have impact on the microelectronics industry. Studies on the structural, elastic, thermal, and electrical properties of heteroepitaxial CoSi2, ReSi2, and GeSi films grown on Si constitute the backbone of this thesis. Some new characteristics of heterostructures were discovered as a result of this investigation. Among them are the observation and modeling of misorientation effects on an epitaxial film grown on a vicinal substrate; the misorientation induced by interfacial misfit dislocation arrays; the experimental measurements and phenomenological analysis of thermal strain, dislocation generation, and strain relaxation; and illustrative measurements of elastic, thermal, and structural properties of epitaxial films.

Ion implantation is an important process in the fabrication of integrated circuits. The second part of this thesis deals with the production and annealing of damage produced by ion implantation in semiconductors. The defect production, stability, microstructure, and the induced strain in implanted bulk Si crystals were quantitatively investigated as a function of ion species, dose, and implantation temperature. Many new features, such as the rapid rise of damage near the amorphization threshold, the correlation between the strain and defect concentration, and the scaling behavior of the damage with ion species and implantation temperature, are revealed.

The last chapter concerns the effects of ion implantation in CoSi2, ReSi2, and GeSi/Si heterostrcutures which is a marriage of heteroepitaxial and of ion implantation studies. Some interesting phenomena, such as the selective damage of the film and the substrate, the superposition of the intrinsic and the induced strain, are observed, and some preliminary results are obtained. Many interesting questions remain, and there are great research opportunities in this relatively unexplored area.

Thesis Files