High effective minority carrier lifetime on silicon substrates using quinhydrone-methanol passivation

Abstract

Iodine-methanol (I2/ME), a chemical passivation method, is extensively used in silicon (Si) solar cell fabrication for measuring minority carrier lifetime in bulk regions. We demonstrate that quinhydrone-methanol (QHY/ME) provides higher lifetimes than I2/ME. For 0.01 mol/dm−3 QHY/ME on float-zone (FZ) wafers at 1×1015 cm−3 injection level, a high lifetime of 3.3 ms and surface recombination velocity of 7 cm/sec on n-type (100 Ω cm) and 1.1 ms on p-type (2 Ω cm) is reported. The surface recombination velocity is also measured out of solution for several days. Chemical characterization results indicate increasing surface oxidation with decreasing passivation, consistent with proposed bonding mechanism.