Basically all properties of semiconductor devices are influenced by the distribution of point defects in their active areas. This book contains the first comprehensive review of the properties of intrinsic point defects, acceptor and donor impurities, isovalent atoms, chalcogens, and halogens in silicon, as well as of their complexes. Special emphasis is placed on compiling the structures, energetic properties, identified electrical levels and spectroscopic signatures, and the diffusion behavior from experimental and theoretical investigations. In addition, the book discusses the fundamental concepts of silicon and its defects, the electron system, diffusion, thermodynamics, and reaction kinetics which form the scientific basis needed for a thorough understanding of the text. Therefore, the book is able to provide an introduction to newcomers in this field up to a comprehensive reference for experts in process technology, solid-state physics, and simulation of semiconductor processes.