Boron is the most important p-type dopant in Si and it is essential that,
especially for low energy implantation, both as-implanted B distributions
and those produced by annealing should be characterized in very great detail
to obtain the required process control for advanced device applications.
While secondary ion mass spectrometry (SIMS) is ordinarily employed for this
purpose, in the present studies implant concentration profiles have been
determined by direct B imaging with approximately nanometer depth and
lateral resolution using energy-filtered imaging in the transmission
electron microscopy. The as-implanted B impurity profile is correlated with
theoretical expectations: differences with respect to the results of SIMS
measurements are discussed. Changes in the B distribution and clustering
that occur after annealing of the implanted layers are also described.