Cu gettering by phosphorus-doped emitters in p-type silicon: Effect on light-induced degradation

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Abstract

The presence of copper (Cu) contamination is known to cause relevant light-induced degradation (Cu-LID) effects in p-type silicon. Due to its high diffusivity, Cu is generally regarded as a relatively benign impurity, which can be readily relocated during device fabrication from the wafer bulk, i.e. the region affected by Cu-LID, to the surface phosphorus-doped emitter. This contribution examines in detail the impact of gettering by industrially relevant phosphorus layers on the strength of Cu-LID effects. We find that phosphorus gettering does not always prevent the occurrence of Cu-LID. Specifically, air-cooling after an isothermal anneal at 800°C results in only weak impurity segregation to the phosphorus-doped layer, which turns out to be insufficient for effectively mitigating Cu-LID effects. Furthermore, we show that the gettering efficiency can be enhanced through the addition of a slow cooling ramp (-4°C/min) between 800°C and 600°C, resulting in the nearly complete disappearance of Cu-LID effects.

Details

Original languageEnglish
Article number015112
Number of pages7
JournalAIP ADVANCES
Volume8
Issue number1
Publication statusPublished - 2018
MoE publication typeA1 Journal article-refereed

    Research areas

  • transition, photodetectors, chemical compounds, doping, heat treatments

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