Contactless optical evaluation of processing effects on carrier lifetime in silicon

Contactless, optical modulation of free‐carrier absorption has been used to identify minority‐carrier lifetime degradation associated with both novel and common very large scale integrated circuit processing steps in p‐type silicon wafers. Carrier lifetime degradation and a corresponding increase in surface recombination velocity was found to be associated with the silicon etchants ethylenediamine‐pyrocatechol‐water (EDP) and potassium hydroxide (KOH), prolonged exposure to hydrofluoric acid (HF and BHF), and ion bombardment associated with a variety of plasma etching steps. Knowledge of process‐induced lifetime degradation obtained by this technique may offer significant input into the development of high‐yield very large scale integrated circuit processes.Contactless, optical modulation of free‐carrier absorption has been used to identify minority‐carrier lifetime degradation associated with both novel and common very large scale integrated circuit processing steps in p‐type silicon wafers. Carrier lifetime degradation and a corresponding increase in surface recombination velocity was found to be associated with the silicon etchants ethylenediamine‐pyrocatechol‐water (EDP) and potassium hydroxide (KOH), prolonged exposure to hydrofluoric acid (HF and BHF), and ion bombardment associated with a variety of plasma etching steps. Knowledge of process‐induced lifetime degradation obtained by this technique may offer significant input into the development of high‐yield very large scale integrated circuit processes.