Inline PECVD Deposition of Poly‐Si‐Based Tunnel Oxide Passivating Contacts

In this publication, the deposition of a‐Si(n) layers using an industrially relevant inline plasma‐enhanced chemical vapor deposition (PECVD) tool for the successful realization of passivating contacts is reported. Dynamic inline deposition has the potential to increase production throughput and yield compared to the conventional cluster‐like PECVD tools which is the current standard for deposition of a‐Si:H layers. Besides structural investigations concerning absorbance and band gap energy of these layers, the dependence of layer thickness and PH₃ gas phase doping on implied open circuit voltage iV_OC, sheet resistance, and the corresponding diffusion profile is investigated. A significant influence of PH₃ gas phase doping is demonstrated whereas no significant dependence of the layer thickness is elaborated. Excellent values of iV_OC = 740 mV and iFF = 85% on planar and iV_OC = 720 mV and iFF = 84% on textured surfaces can be reached implementing the developed n‐doped layers in the tunnel oxide passivating contact (TOPCon) structure.