Reactive ion etched, self-aligned, selective area poly-Si/SiO 2 passivated contacts

Young, David L.; Chen, Kejun; Theingi, San; LaSalvia, Vincenzo; Diercks, David; Guthrey, Harvey; Nemeth, William; Page, Matthew; Stradins, Pauls

doi:10.1016/j.solmat.2020.110621

DOE OSTI · 1726066

Reactive ion etched, self-aligned, selective area poly-Si/SiO 2 passivated contacts

Young, David L.·Chen, Kejun·Theingi, San·LaSalvia, Vincenzo·Diercks, David·Guthrey, Harvey·Nemeth, William·Page, Matthew·Stradins, Pauls

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Abstract

Front/back poly-Si/SiO 2 contact devices suffer from low short-circuit current density, J sc , due to parasitic optical absorption in the front poly-Si layer. Thin poly-Si (~20 nm) allows for high J sc but is not compatible with screen-printed fire-through contacts. We therefore study the effects of post-deposition etching of a thick poly-Si (200 nm) front layer by reactive ion etching (RIE) using the metal grid lines as a self-aligned mask. We show that passivation is maintained in the device during RIE and that J sc is increased by a gain in the blue quantum efficiency response. However, our specific etching parameters cause non-uniform etching of the poly-Si leading to premature loss of passivation without optimal gain in J sc . Etched, unpassivated layers can be re-passivated with a H-containing dielectric layer leading to a gain in Jsc, open circuit voltage, V oc , Fill-Factor, FF, and efficiency.

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Young, David L., Chen, Kejun, Theingi, San, LaSalvia, Vincenzo, Diercks, David, Guthrey, Harvey, Nemeth, William, Page, Matthew, Stradins, Pauls. 2020-09-04. Reactive ion etched, self-aligned, selective area poly-Si/SiO 2 passivated contacts. https://doi.org/10.1016/j.solmat.2020.110621

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