Defects in Semiconductors: Some Fatal, Some Vital
Hans J. Queisser,
*
Eugene E. Haller
REVIEW
The role of defects as essential entities in semiconductor materials is
reviewed. Early experiments with semiconductors were hampered by the
extreme sensitivity of the electronic properties to minute
concentrations of impurities. Semiconductors were viewed as a family of
solids with irreproducible properties. Scientific efforts overcame this
idiosyncrasy and turned the art of impurity doping into today's
exceedingly useful and reproducible technology that is used to control
precisely electrical conductivity, composition, and minority-carrier
lifetimes over wide ranges. Native defects such as vacancies and
self-interstitials control basic processes, foremost self- and dopant
diffusion. The structural properties of dislocations and higher
dimensional defects have been studied with atomic resolution, but a
thorough theoretical understanding of their electronic properties is
incomplete. Reactions between defects within the host lattices are
increasingly better understood and are used for gettering and
electrical passivation of unwanted impurities. Metastable defects such
as DX centers and the EL2-related arsenic antisite are briefly
discussed. The recent development of isotopically controlled
semiconductors has created new research opportunities in this field.
Department of Materials Science and Mineral Engineering,
University of California and Lawrence Berkeley National Laboratory,
Berkeley, CA 94720, USA.
*
Miller Institute Visiting Professor, on leave from Max-Planck-Institut
für Festkörperforschung, D-70506 Stuttgart, Germany.
