Choice of electrolyte for doping pro®ling in Si by electrochemical C±V technique

Commonly used electrolytes (NH4F HF and NaF/H2SO4) for doping pro®le analysis in Si are employed to clarify their capabilities and limitations using a boron-doped staircase test structure. The carrier density pro®les at various measurement voltages for these electrolytes are compared with a SIMS pro®le of the structure. A variety of parameters affecting a carrier density pro®le such as static current±voltage behaviour, dissipation factor, ¯at band potential and series resistance at various doping levels are explored to optimise the measurement conditions. It is found that both electrolytes can be employed for doping pro®ling in Si for a broad range of doping levels. However, electrolyte NaF/H2SO4 allows wider measurement voltage range and suits better for pro®ling highly doped structures as indicated by lower series resistance and hence lower dissipation factor. # 2001 Elsevier Science B.V. All rights reserved