Nitrogen and aluminum implantation in high resistivity silicon carbide

In this article, the results on N and Al implantations into undoped high-resistance and vanadium doped semi-insulating bulk 6H-SiC are reported for the first time. The N implants were performed at 700 degrees C and the Al implants at 800 degrees C to create n- and p-type layers, respectively. For comparison, implants were performed into epitaxial layers at the above temperatures and, for N, also at room temperature. The implanted/annealed material was characterized by van der Pauw Hall, secondary ion mass spectrometry, and Rutherford backscattering (RES) measurements. After annealing, the room temperature N implantation gave similar electrical and RES results as the 700 degrees C implantation for a total implant dose of 8x10(14) cm(-2) which corresponds to a volume concentration of 2x10(19) cm(-3). The Al implant redistributed in the bulk crystals during annealing, resulting in a shoulder formation at the tail of the implant profile. Lower implant activation was obtained in V-doped material compared to the undoped bulk and epitaxial layers, but the results were promising enough to use implantation technology for making planar high frequency devices in the bulk V-doped substrates, especially as the quality of the substrates continue to improve. (C) 1997 American Institute of Physics.