Surface dopant concentration measurement using the Surface Charge Profiler (SCP) method: characterization of hydrogen and metallic contamination in silicon

Boron deactivation by pairing with contaminants and boron compensation are studied in silicon wafers from various IC manufacturing processes using the Surface Charge Profiler (SCP) method. Dissociation energies of pairs formed due to noble metals contamination in HF chemistries are the same independently of the noble metal and correspond to the one of B–H pairs. This suggests that metals are not directly responsible for the doping change but enhance hydrogen contamination into the silicon during HF cleaning. Hydrogenation during SC1 clean (ammonium hydroxide–peroxide mixture), RCA clean (RCA=SC1+SC2 where SC2 is hydrochloric acid–peroxide mixture), and plasma etching is responsible for boron deactivation through B–H formation. Copper contamination introduced into Si during thermal oxidation compensates initial boron doping by formation of stable complexes.