Wafers of 6H–SiC n-type material were implanted with Al+ and N+ ions in 2 steps: firstly N+ double-implantation (65keV, 5 x 1016/cm2 and 120keV, 1.3 x 1017/cm2) followed by Al+ double implantation (100keV, 5 x 1016/cm2 and 160keV, 1.3 x 1017/cm2). The implantation was carried out at a substrate temperature of 800C, in order to avoid amorphization. In this way, a buried (SiC)1-x(AlN)x layer could be created. Variable-energy positron Doppler broadening measurements were performed at room temperature by using a magnetic transport beam system to characterize the vacancy-type defects created by ion implantation. The depth profiles could be evaluated from the measured Doppler broadening profiles. The defect distribution and the defect size after complete co-implantation were analyzed, and the contributions which the various implantation steps made to the evolution of the defect structure was shown.

Vacancy-Type Defects in 6H–SiC Caused by N+ and Al+ High-Fluence Co-Implantation. W.Anwand, G.Brauer, W.Skorupa: Applied Surface Science, 2002, 194[1-4], 131-5. See also: Applied Surface Science, 2001, 184[1-4], 247-51