SELF-COMPENSATION IN SEMICONDUCTORS - A REVIEW DEDICATED TO THE 100THANNIVERSARY OF THE BIRTHDAY OF FRENKEL,YAKOV,ILICH

The current state of the problem of self-compensation in semiconductor s is reviewed. This effect consists of a limitation on the density of electrons (or holes) in a semiconductor in comparison with the concent ration of the primary dopant, i.e., shallow donors (or acceptors). In this case the doping itself stimulates processes which prevent a shift of the Fermi level toward the conduction or valence band. Various mod els of self-compensation are discussed. They involve the formation of intrinsic compensating defects, the formation of defect-impurity compl exes, and a relaxation of the lattice near an impurity atom accompanie d by the formation of a bistable impurity state. Experimental manifest ations of self-compensation in covalent crystals, III-V and II-VI comp ounds, and also amorphous semiconductors indicate that different self- compensation mechanisms probably operate in different materials. The e ffectiveness of these mechanisms is governed by such parameters as the width of the band gap, the covalent or ionic radius of the impurity, and the binding energy of the atoms in the lattice. (C) 1994 American Institute of Physics.