Solid solubility is not a limiting factor for the maximum activation of
impurities during solid phase epitaxial recrystallization (SPER). However, activation is
limited to the maximum value of about 2x1020 cm-3 during SPER. A concept of the
isolated impurity that has no neighbor impurities with a certain lattice range is
introduced. The impurities react with neighbor impurities to form clusters, and only the
isolated impurities can be active. The isolated impurity concentration has the maximum
concentration at the total impurity concentration of about 1021 cm-3, and it decreases
with a further increase in total impurity concentration.
Keywords: Ion implantation, solid solubility, solid phase epitaxy, phosphorus,
activation, isolated impurity, point defects, thermal equilibrium, shallow junction,
cluster, amorphous layer, sheet resistance, annealing, furnace annealing, reverse
annealing, spreading resistance.