Characterization of buried silicon-nitride formed by nitrogen implantation

High temperature (420-450 degrees C) N2+-implantations at 300 keV (150 keV per atom) into high resistivity p-type (001)-silicon substrates yield buried amorphous SiNx-layers for N-doses ranging from .1 to 1 x E18 cm-2. Thermal anneal at 1200 degrees C in dry N2-atmosphere leads to epitaxial crystallization of the silicon matrix with embedded SiNx-precipitates of three different orientations relative to the Si-matrix. At high doses these nitride grains eventually form a continuous insulating alpha-Si3N4 layer. Detailed optical, AES and TEM investigations have been performed to study the nucleation and grain growth for different N-concentrations in the profile maximum. The main topic of this paper is the structural TEM analysis of the early stages of grain growth. (IMS)