DENSITY AND STRUCTURAL-CHANGES IN SIC AFTER AMORPHIZATION AND ANNEALING

The density of amorphous SiC layers formed by 2 MeV Si+ implantation i nto single-crystalline 6H-SiC was measured by x-ray reflectometry and compared with the results of step height measurements. Reactive ion et ching was used to investigate the density as a function of depth. The density of the as-amorphized SiC is about 12% less than that of the cr ystalline material. Within experimental accuracy, the density reductio n is homogeneous across the whole layer thickness. Low-temperature ann ealing leads to the formation of relaxed amorphous SIC with a density about 7% below the crystalline one. These large density changes are in contrast to results in amorphous Si. They can be explained by the hig h atomic density of SiC and the chemical disorder in the amorphous sta te of SiC. (C) 1997 American Institute of Physics.