Comparison of high-resistivity silicon surface passivation methods

This paper describes low-frequency measurements and comparative analysis of methods used for surface passivation of high-resistivity silicon (HR-Si). A number of substrates are evaluated; n-type and p-type HR-Si, with and without surface passivation by means of polysilicon or Ar-ion implantation. Additionally, a selection of samples is prepared with a layer of ferroelectric material. Substrate characteristics are extracted from measurements of the samples, allowing comparison of passivation methods and evaluation of the influence of the ferroelectric film. The study shows all passivation methods successful in removing any bias-dependence of substrate properties. Further, the high-temperature processing of the ferroelectric film is observed increasing the extracted substrate conductivity by about 70% for the Ar-ion implanted samples, and about 50% for the p-type samples passivated by poly-Si. The effective substrate conductivity of the n-type samples passivated by RTA-crystallised poly-Si appears unaffected.