EFFECTS OF THICKNESS ON DISLOCATIONS IN GAP ON SI GROWN BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION

GaP grown on Si under high V/III ratio by means of metalorganic chemic al vapor deposition has been characterized by using conventional and h igh-resolution transmission electron microscopy. GaP has been grown on Si two-dimensionally from the beginning of the growth under high V/II I ratio. Dislocations are not observed when the GaP layer-thickness is less than 90 nm. On the other hand, dislocations are observed at the interface when the GaP layer is thicker than 90 nm. The dislocation de nsity at the interface increases and the GaP/Si interface becomes wavy with increasing thickness. The origins of these dislocations are the thermal stress and the lattice mismatch.