The Role of Defects in Semiconductor Materials and Devices

This literature review leads to the conclusion that recently the basis for an understanding of the electrical and optical properties of structural defects in semiconductors, especially in silicon, has begun to emerge. This is due largely to the ability of scanning electron microscopy (SEM) electron beam induced current (EBIC) and cathodoluminescence (CL) to determine the properties of single, well-defined defects in state of the art material. However, there are still major differences concerning the physical models to be used to explain different forms of dislocation EBIC contrast variation with temperature and beam current. Basic ideas in this field are emphasized. In contrast, there has been little systematic fundamental study of the role of defects in devices. Well-known correlations of properties with dislocation densities show that defects in materials and devices are undesirable, although the numbers that can be tolerated are often large and vary greatly from one material to another. Proposals to exploit defects in devices have not been adopted in practice. The few particular cases of the physical mechanisms of the influence of defects on device performance that have been studied are outlined. The role of defects in devices is ripe for the application of scanning beam techniques