RECENT PROGRESS IN GAAS ON SI TECHNOLOGY - CONCERNING THE REDUCTION OF THREADING DISLOCATION

The practical application of GaAs on Si technology into combining optoelectronic and high-speed devices is our hopefully rewarding long-term objective. To achieve this, the defect density in GaAs on Si needs to be reduced from a value of approximately 10(6)/cm2, which is the ordinal defect density obtained by the present state-of-the-art GaAs on Si technology, to values obtainable in bulk or homoepitaxial GaAs (< 10(4)/cm2). We discuss in the present paper recent progress of GaAs on Si technology from the viewpoint of how to be able to suppress the threading dislocation density in GaAs layers to the level of 10(4)/cm2 on the basis of recently obtained results. In particular, the effects of new approaches for realizing two-dimensional growth, new materials for buffer layers and insertion layers, high-temperature annealing, ion beam irradiation and the confinement of growth areas on the reduction of threading dislocation generation and propagation, are discussed.