RAPID THERMAL-DIFFUSION OF BORON IMPLANTED AS BORON DIFLUORIDE IN PREAMORPHIZED SILICON

The diffusion of boron, implanted into crystal and preamorphized silicon in the form of boron difluoride, has been studied using secondary-ion mass spectroscopy and cross-sectional transmission electron microscopy. A 90-keV silicon implant creates an amorphous layer extending from the silicon surface to a depth of 186 nm as measured by Rutherford backscattering spectroscopy. The as-implanted boron profiles are contained completely within the amorphous layer. Results indicate that boron diffusion in the amorphous layer is suppressed during rapid thermal annealing between 1000 and 1150-degrees-C. Discussion of this is based on the effect of fluorine on the boron diffusion.