Positron Annihilation in Semiconductors

The subject of this book is the investigation of lattice imperfections in semiconductors by means of positron annihilation. The sensitivity range of positron annihilation with respect to the detection of these defects is compared to that of other defect-sensitive methods. The electrical and optical properties of semiconductors are dominated by lattice defects. Positron annihilation has become one of the most important techniques for the investigation of vacancy-like defects. Positrons may be captured in lattice imperfections and the annihilation signal then contains specific information on the type and the concentration of these defects. A comprehensive overview of positron studies in elemental and compound semiconductors is presented. Emphasis is put on investigations of defects in as-grown, electron-irradiated, ion-implanted, and plastically deformed material. It is shown how positrons can be used to profile structural defects in epitaxial layers and at interfaces. Possible applications of positron annihilation in defect engineering are discussed. The theoretical foundations of the interaction of positrons with matter are reviewed. The book describes in detail all important techniques of positron annihilation, such as positron lifetime spectroscopy, Doppler-broadening spectroscopy, the angular correlation of annihilation radiation, positron-beam applications, and also new methods. The sensitivity and selectivity of defect detection by positron annihilation is compared to other characterization methods. The subject of this book is the investigation of lattice imperfections in semiconductors by means of positron annihilation. A comprehensive review is given of the different positron techniques, whose application to various kinds of defects, e.g. vacancies, impurity-vacancy complexes and dislocations, is described. The sensitivity range of positron annihilation with respect to the detection of these defects is compared to that of other defect-sensitive methods. The most prominent results obtained with positrons in practically all important semiconductors are reviewed. A special chapter of the book deals with positron annihilation as a promising tool for many technological purposes. The theoretical background necessary to understand the experimental results is explained in detail.