Published online by Cambridge University Press: 28 February 2011
Buried silicon nitride layers are formed by high temperature (600-800°C), high dose (0.3-1 x 1018 Ncm -2) nitrogen implantation into silicon. The nitride structure of as-implanted and annealed (6 h at 1200°C) samples is revealed by TEM-analysis. At implantation temperatures up to 600°C an amorphous SixN" layer is formed. At higher temperatures crystalline precipitates are found within an amorphous environment. They are identified as β-Si3N4 by electron diffraction. By subsequent annealing the previously amorphous material crystallizes to a-Si3N4, while the β-grains seem to be stable.