Interactions of high-energy Si, Zn and Ga ions with dislocations in GaAs on Si

Abstract

The interactions between the pre-existing dislocations in GaAs on Si and the excess point defects introduced by MeV energy Si-, Zn- and Ga-ion implantation have been investigated mainly using cross-sectional transmission electron microscope observations. The formation of helical dislocations, which have a /2〈110〉 type Burgers vectors parallel to the axes of the helices, is detected in all the implanted layers. The degree of the helical feature, for example, the radii of the dislocation helices, strongly depends on the dose and mass of the implanted ions and annealing temperatures. The dislocation helices disappear after annealing at 600°C independent of implantation conditions. The depth distribution of the helical dislocations is discussed taking into consideration the primary defects (vacancies) distribution in the implanted layers.