LeTID mitigation via an adapted firing process in p‐type PERC cells from SMART cast‐monocrystalline, Czochralski and high‐performance multicrystalline silicon

Abstract

AbstractIn this work, we analyse passivated emitter and rear cells (PERC), based on wafers made from seed manipulation for artificially controlled defects technique (SMART) monocrystalline silicon, magnetically grown and conventional Czochralski (mCz and Cz) silicon, and high‐performance multicrystalline (hpm) silicon. All wafers were processed identically except for the hpm wafers, which received an acidic texture instead of random pyramids. The energy conversion efficiencyηof the SMART cells of 21.4 %is similar to the mCz cells (21.5 %) while being more thanhigher than for the hpm cells. Furthermore, we here show for the first time that light‐ and elevated temperature‐induced degradation (LeTID) is mitigated in hpm, Cz and SMART PERC cells without significant losses in initial efficiency by an adapted fast‐firing process, incorporating slower firing ramps that can be used in industrial production. The cells that are fired with these ramps show no significant efficiency loss () during LeTID testing at 75°C and 0.15 suns illumination for 1100 h, while the reference fast‐firing process results in efficiency losses ofdue to LeTID. For Cz cells that have been treated to regenerate the boron–oxygen defect prior to LeTID testing, the maximum degradation was reduced fromto.