DOSE DEPENDENCE OF MICROSTRUCTURAL DEVELOPMENT OF BURIED OXIDE IN OXYGEN-IMPLANTED SILICON-ON-INSULATOR MATERIAL

The effect of implantation dose on microstructural development of the buried oxide (BOX) of 200 keV oxygen implanted Si was studied by elect ron microscopy, A continuous BOX layer with a low density of Si island s was obtained for a dose of 0.45 X 10(18) cm(-2), following high temp erature annealing. At a lower dose of 0.225 x 10(18) cm(-2) a layer di d not form, but only disjointed, isolated, oxide precipitates develope d. At a higher dose, 0.675 X 10(18) cm(-2), a continuous BOX layer wit h a high density of Si islands formed. Microstructures of intermediate -temperature annealed samples showed the formation of oxide precipitat es at preferred depths, the morphology being dose dependent. The final microstructure of the BOX is strongly influenced by the evolution of the oxide precipitates during annealing. A qualitative mechanism is pr oposed for the dose-dependent behavior of BOX formation during the ann ealing process. (C) 1997 American Institute of Physics.