Easy-to-use surface passivation technique for bulk carrier lifetime measurements on silicon wafers

A novel, easily applicable surface passivation technique is presented, which, in combination with contactless photocoductance decay (PCD) measurements, allows a quick estimation of the bulk carrier lifetime of crystalline silicon wafers. The proposed passivation technique requires neither a chemical pre-cleaning of the silicon wafer nor expensive instrumentation. On both surfaces of the wafer a thin varnish film is deposited using a spinner. Subsequently, both surfaces of the coated silicon wafer are charged by means of a corona chamber. Using microwave-detected PCD measurements, we experimentally demonstrate that this novel surface passivation scheme provides differential surface recombination velocities in the 30–70 cm s−1 range on p-as well as n-type silicon wafers.