Annealing of Al implanted 4H silicon carbide

Al ions were implanted with multiple energies up to 250 keV at elevated temperatures in n-type 4H SiC epitaxial layers to reach a surface concentration of 1 x 10(20) cm(-3). These samples were then annealed at temperatures between 1500 and 1950 degrees C. A similar 4H SiC epitaxial sample was implanted by MeV Al ions to lower doses and annealed only at 200 and 400 degrees C. After annealing, cross-sections of the samples were characterized by scanning spreading resistance microscopy (SSRM). The results show that the resistivity of high-dose Al implanted samples has not reached a saturated value, even after annealing at the highest temperature. For the MeV Al implanted sample, the activation of Al has not yet started, but a substantial annealing of the implantation induced damage can be seen from the SSRM depth profiles.