Shallow buried SiNx layers

High dose nitrogen implantations have been performed at an energy of 30 keV . After high temperature annealing, 1200 degrees C, a buried layer composed mostly of silicon nitride is formed leaving an overlayer with a high fract ion of crystalline silicon. The lattice constant of the overlayer and the r egion below the SiNx are reduced in 0.13% and 0.089%, respectively. The sub stitutional N seems to be responsible for this reduction. (C) 2000 American Institute of Physics. [S0021-8979(00)00211-5].