NITROGEN AND ALUMINUM IMPLANTATION IN HIGH-RESISTIVITY SILICON-CARBIDE

In this article, the results on N and Al implantations into undoped hi gh-resistance and vanadium doped semi-insulating bulk 6H-SiC are repor ted 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 l ayers 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 ga ve similar electrical and RES results as the 700 degrees C implantatio n for a total implant dose of 8x10(14) cm(-2) which corresponds to a v olume concentration of 2x10(19) cm(-3). The Al implant redistributed i n the bulk crystals during annealing, resulting in a shoulder formatio n at the tail of the implant profile. Lower implant activation was obt ained in V-doped material compared to the undoped bulk and epitaxial l ayers, but the results were promising enough to use implantation techn ology for making planar high frequency devices in the bulk V-doped sub strates, especially as the quality of the substrates continue to impro ve. (C) 1997 American Institute of Physics.