Defects and future semiconductor devices

Two of the most important technological trends for future devices have been mismatched epitaxy and strained layer superlattices. This makes possible, for example, the growth of device quality GaAs on silicon wafers. In case where the mismatch strain is coherent, novel material and device properties are possible, such as GeSi/Si superlattices on silicon. In such systems the role of defects is particularly important. Recent work has shed considerable light on the criteria for producing such strained layers without mismatch dislocations. In cases such as GaAs on Si where defects seem unavoidable, it has been found by DLTS that electron traps can be avoided sufficiently far from the interface. Recent results in this system indicate that FETs are unaffected by the mismatched interface, whereas devices such as lasers, which undergo electron-hole recombination, have severe degradation problems. This talk will give an overview of this newly emerging area where the control of defects is critical to future developments. (author) 29 refs., 12 figs