The Use of Superlattices to Block the Propagation of Dislocations in Semiconductors

Abstract

ABSTRACTSince the discovery in 1973 that GaAs/GaAsP superlattices can be grown with low dislocation densities, considerable interest has developed in utilizing superlattices as dislocation filters in multilayer semiconductor device structures. Many attempts to implement this process have been described, with varying degrees of success being achieved. Some investigators have reported favorable results; some have observed no effect; and in some cases the situation was actually made worse. This paper analyzes these reports and attempts to clarify the confusion that has arisen. Suggestions are made for improved effectiveness. Factors considered include the strain between layers, the layer thickness, the concept of critical thickness, the dislocation geometry, and the influence of buffer layers and growth conditions.