Written by P. J. Timans & N. Acharya, Mattson Technology

ABSTRACT

Low-energy ion implantation can be combined with millisecond-duration annealing at temperatures just below the melting point of silicon to form very shallow junctions with a high degree of electrical activation. A prototype pulsed heating system based on a xenon flash lamp was used to study the annealing of low-energy B-implants in silicon. The sheet resistance and junction depth results suggest that this approach can meet the requirements for highly scaled MOS devices. Despite these encouraging results, millisecond annealing faces many difficult challenges before it can be implemented in volume manufacturing. The large temperature gradients and thermal stresses induced in the wafer by pulsed energy sources or scanned energy beams present formidable challenges for process control.