Physical processes associated with the deactivation of dopants in laser annealed silicon

Laser annealing is being investigated as an alternative method to activate dopants and repair the lattice damage from ion implantation. The unique properties of the laser annealing process allow for active dopant concentrations that exceed equilibrium solubility limits. However, these super-saturated dopant concentrations exist in a metastable state and deactivate upon subsequent thermal processing. Previously, this group compared the electrical characteristics of the deactivation behavior of common dopants (P, B, and Sb) across a range of concentrations and annealing conditions. Boron and antimony were shown to be stable species against deactivation while P and As deactivate quickly at temperatures as low as 500 degreesC. In this work, we present additional data to understand the underlying physical mechanisms involved in the deactivation process. It is proposed that As and P deactivate through the formation of small dopant-defect clusters while B and Sb deactivate through precipitation. (C) 2002 American Institute of Physics.