Non-Contact and Non-Destructive Characterization Alternatives of Ultra-Shallow Implanted Silicon p-n Junctions by Multi-Wavelength Raman and Photoluminescence Spectroscopy

Abstract

Ultra-shallow boron implanted ( ) n-type Si wafers were prepared and characterized by multi-wavelength Raman and photoluminescence (PL) spectroscopy before and after rapid thermal annealing (RTA). The Raman and PL characterization results were compared with sheet resistance from four point probe measurements and boron depth profiles from secondary ion mass spectroscopy. We have found a very strong correlation between the rapid, non-contact optical characterization results and important parameters of ultra-shallow junctions (USJs) obtained from conventional invasive techniques. Ultraviolet Raman was very sensitive to subsurface B profiles near or above the solid solubility of B in Si. Visible wavelength excitation PL indicated the presence of significant levels of nonradiative recombination centers beyond the USJ depth and implant end-of-range damage even after RTA. Multi-wavelength Raman and PL are found to be very promising as complementary and/or alternative diagnostic metrology tools for implant process control and in-line device performance screening.