A First Principles Study of Hydrogen Related Defects in Silicon

PhD Thesis Submitted by B. Hourahine to the University of Exeter for the degree of Doctor of Philosophy in Physics, March 2000.

The results of first principles calculations are presented for several types of point defect in crystalline silicon that contain hydrogen. The information presented in this work is derived using cluster and supercell geometries within the local density functional theory.

The properties of molecular hydrogen within bulk silicon are considered and compared with recent experimental observations. The interaction between hydrogen molecules and other defects such as chemically inert voids or oxygen impurities are also examined.

Several defects which have been suggested to form in proton-implanted silicon are examined. The behaviour of hypothetical complexes between silicon self-interstitials and several hydrogen atoms are examined in an attempt to resolve a long standing argument over the nature of two families of complexes between native defects and hydrogen. A new form of hydrogen dimer which is suggested to form in such material is simulated for the first time, and compared against both experiment and other dimer structures.

The interaction of hydrogen with multiple vacancies in the silicon lattice is simulated, leading to an assignment for a large family of optically active defects as complexes between hydrogen and the largest vacancy centre so far observed in silicon.

The behaviour of complexes between hydrogen and isolated carbon impurities, which substitute for silicon atoms in the lattice, is simulated, allowing a consistent model for two sets of apparently disparate experimental observations to be suggested.

The thesis is available as PDF (11.5 M) and PostScript (10.4 M).

Last modified: Tue Nov 14 12:09:16 GMT 2000 by B. Hourahine