Time-dependent diffusivity of boron in silicon oxide and oxynitride

The diffusivities of boron in silicon oxide and oxynitride have been determ ined from secondary ion mass spectroscopy measurements of annealed metal-ox ide-silicon structures. The results clearly show a decrease in diffusivity with increasing anneal time which is approximately exponential in form. Thi s effect implies a similar time dependence in the concentration of a second ary species, such as hydrogen, or a defect within the dielectric, which pro motes diffusion even in a nominally pure oxide. (C) 1999 American Institute of Physics. [S0003-6951(99)03207-6].