Properties of nitrogen-implanted SOI substrates

Properties of nitrogen-implanted silicon-on-insulator (SOI) substrates prepared by implanting different doses of 200 keV nitrogen into 50-70 Omega -cm, p-type silicon substrates at a temperature of 500 degrees C were studied. The distribution of nitrogen was studied using Auger electron spectroscopy. The electrical properties of the active overlayer were studied using Hall-effect measurements and capacitance-voltage depth profile analysis. The insulating integrity of the buried nitride was studied by directly measuring the leakage current from top to bottom through the substrate. Additionally, electric field strength and surface roughness measurements were performed. Nitrogen concentrations in the buried layer increased from below to above the stoichiometric value for Si/sub 3/N/sub 4/ for increasing dose in the range studied. Nitrogen-related n-type doping is observed in all samples examined, and the magnitude of the doping increased with the increasing implant dose. Insulating buried nitride layers are formed only in samples implanted with very high doses.<
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