The reverse anneal of junction characteristics in forming shallow p/sup +/-n junction by BF/sub 2//sup +/ implantation into thin Co films on Si substrate

Silicided shallow p/sup +/-n junctions, formed by BF/sub 2//sup +/ implantation into thin Co films on Si substrates and subsequently annealed, showed a reverse anneal of junction characteristics in the temperature range between 550 and 600 degrees C. The reverse anneal means behavior showing degradation of the considered parameters with increasing annealing temperature. A higher implant dosage caused a more distinct reverse anneal. The reverse anneal of electrical characteristics was associated with the reverse anneal of substitutional boron. A shallow p/sup +/-n junction with a leakage current density lower than 3 nA/cm/sub 2/, a forward ideality factor of better than 1.01, and a junction depth of about 0.1 mu m was achieved by just a 550 degrees C anneal.<>