Choice of electrolyte for doping profiling in Si by electrochemical C-V technique

Abstract

Commonly used electrolytes (NH4F . HF and NaF/H2SO4) for doping profile analysis in Si are employed to clarify their capabilities and limitations using a boron-doped staircase test structure. The carrier density profiles at various measurement voltages for these electrolytes are compared with a SIMS profile of the structure. A variety of parameters affecting a carrier density profile such as static current-voltage behaviour, dissipation factor, flat 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 profiling in Si for a broad range of doping levels. However, electrolyte NaF/H2SO4 allows wider measurement voltage range and suits better for profiling highly doped structures as indicated by lower series resistance and hence lower dissipation factor, (C) 2001 Elsevier Science B.V. All rights reserved.