Very low surface recombination velocity of boron doped emitter passivated with plasma-enhanced chemical-vapor-deposited AlOx layers

Abstract In this work, we present a systematic study of the surface recombination velocity of boron-diffused Si wafer passivated with plasma-enhanced chemical-vapor-deposited (PECVD) AlO x layers. Saturation current densities in the range of 5.2–38 fA cm − 2 (at 300 K) were achieved on planar surfaces. In particular, we present an industrially relevant boron emitter, allowing for about 700 mV open circuit voltage on textured surfaces, after a firing process. This high passivation quality could be achieved using AlO x passivation layers deposited by PECVD. The passivation quality is found to be equivalent to AlO x layers deposited by plasma-assisted atomic-layer-deposition. A wide range of surface doping concentration (2.5–70 × 10 18 cm − 3 ) was investigated. The emitters used here allow a high resolution in the determination of the surface recombination velocity upper limit. Our simulations, based on Fermi-Dirac statistics, indicate that only very shallow emitters can be used to further increase the resolution on the determination of the surface recombination velocity.