Using boron cluster ion implantation to fabricate ultra-shallow junctions

Abstract

B/sub 18/H/sub x//sup +/ and B ion implantation have been used to fabricate the SDE of pMOSFETs with gate lengths of /spl sim/60 nm. Ultra high resolution mass spectra of natural abundance B/sub 18/H/sub 22/ and mass 11 isotopically enriched B/sub 18/H/sub 22/ have been used to achieve deconvolution of the binominal distribution from ion states present in the cluster ion beam. The cluster source has been specifically designed to maintain the integrity of the cluster during the ionization process. The results of B/sub 18/H/sub x//sup +/ and B are compared from the viewpoint of transistor performance. The implants were performed at equivalent process energies and doses. It has been shown that B implantation greatly increases the throughput of low energy boron implants while delivering uncompromised device performance.