Ion beam sputter etching of galliumnitride grown by chloride transport LP–CVD

Abstract Galliumnitrid (GaN) layers, grown by chloride transport LP–CVD, were etched by ion beam sputtering with carbon dioxide (CO 2 ). Before etching all samples were masked by electron beam evaporated titanium. We report on the dependence of the etch rate on the angle of incidence of the ion beam. Furthermore we present structural examinations of the surface before and after ion etching as well as an analysis of masking effects. Surface roughening and structural defects were investigated by optical microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM).