DEFECTS IN ION-IMPLANTED 3C-SIC PROBED BY A MONOENERGETIC POSITRON BEAM

Defects introduced by 200-keV N-2(+)- or Al+-implantation into 3C-SiC were probed by a monoenergetic positron beam. Depth profiles of the de fects were determined from measurements of Doppler broadening profiles of the annihilation radiation as a function of incident positron ener gy. For ion implanted specimens at high substrate temperature (greater than or equal to 800 degrees C), the major species of defects was ide ntified to be vacancy clusters. The depth profile of vacancy-type defe cts was found to be shifted towards the surface of the specimen by imp lantation at high temperatures. Upon furnace annealing after the impla ntation, an agglomeration of vacancy-type defects was observed, and in terstitial clusters were introduced below the vacancy-rich region.