Boxer cross measurements of laser annealed shallow junctions

This paper discusses the characterization of the physical processes associated with the formation of ultra-shallow junctions using laser thermal annealing (LTA). Wafers were implanted with a Ge preamorphization implant (PAI) followed by a dopant implant of B, P, or As. The samples were then LTA processed with energies from below to above the energy density required to fully melt the PAI layer. The Boxer Cross CI Carrier Illumination/sup TM/ (CI) method was used to probe the LTA processed samples. The CI method utilizes a laser to photoelectrically generate charge carriers in silicon samples. A second laser beam is reflected by variations of the index of refraction resulting from depth variation of the induced carrier density. The transition in the CI response between amorphous recrystallization and the fully formed laser annealed junction is the subject of this investigation. The details of the dopant distribution, PAI depth, and degree of recrystallization are studied with SIMS and TEM imagery and compared to the CI signal and sheet resistance as functions of LTA energy.