Influence of cryogenic dry etching on minority carriers lifetime in vertically aligned silicon nanostructures

The paper presents the results of the study of the effect of plasma etching of n-type silicon spin-coated with polystyrene balls on bulk silicon properties using careful surface chemical treatments and passivation. Plasma etching was carried out under different substrate temperatures (up to -140 °C). Photoluminescence decay time imaging was used to evaluate effective carrier lifetime in silicon samples after dry etching and a-Si:H passivation. According to the results obtained, plasma etching of n-Si(100) spin-coated with polystyrene balls within the temperature up to -140 °C in gas mixture of SF6/O2, RF and ICP plasma power of 30 W and 1000 W, respectively leads to minority carrier lifetime decrease. The difference in the rate of carrier lifetime degradation with etching time was found.