Study on the Interfacial Oxide in Passivating Contacts

This paper discusses how differently grown ultra-thin interfacial oxide of poly-Si based passivating contacts correspond to high-temperature annealing as well as its sensitivity to hydrogenation. It will be shown on symmetrical lifetime samples that tunnel oxide passivating contacts (TOPCon) featuring thermally grown interfacial oxide layer allow a higher optimum annealing temperature than those with thin wet-chemically grown oxides. These TOPCon structures can yield an excellent passivation quality with up to 741 mV iV(oc) and 88% iFF. Moreover, TOPCon samples annealed at low temperatures benefit more strongly from a subsequent hydrogenation process.