The accuracy of the standard resistivity–concentration conversion practice estimated by measuring the segregation coefficient of boron and phosphorous in Cz‐Si

Abstract

The effective segregation coefficient of boron and phosphorous has been extrapolated from resistivity data collected for a large number of commercial Cz‐Si crystals, pulled in similar experimental conditions. A small solidified fraction of the Si melt volume and different initial concentrations of the doping species in the melt have been considered in this study. The dopant concentration in the solid phase has been estimated by converting the resistivity of the Si crystal to the corresponding dopant concentration, according to the standard conversion practice recommended by SEMI. A dependence of the effective segregation coefficient on the initial dopant concentration in the melt has been found experimentally for two specific ranges of concentration. A possible explanation for such dependence, including the effect of the crucible dissolution and the local inaccuracy of the standard resistivity–concentration conversion procedure, is suggested.

Effective lifetimes exceeding 300 μs in gettered p-type epitaxial kerfless silicon for photovoltaics

“…As-grown wafers are exfoliated and laser-cut into approximately 4 Â 4 cm 2 samples. Bulk resistivity is measured with a four-point probe (Keithley 4200, Cascade Microtech probe), yielding 0.50 X cm (Gen I) and 1.79 X cm (Gen II), with doping concentrations 24 and carrier diffusivities subsequently calculated. First, we describe the processing and characterization performed on the material.…”

Evaluation of advanced p‐PERL and n‐PERT large area silicon solar cells with 20.5% energy conversion efficiencies

“…One perceived issue about n‐type CZ Si is its large resistivity gradient from bottom to top of the ingot, typically, a factor 10 while it is only a factor 3 on p‐type, because of its lower segregation coefficient . Such a high resistivity gradient is seen as a potential disadvantage for production as only a fraction of the ingot might provide sufficient lifetime and also might require wafer sorting plus subsequent adaptation in the process (change of contact pitch to control bulk resistance).…”