EU PVSEC Programme Online
EU PVSEC 2021, 6 - 10 September 2021
Presentation: 2DV.3.4 Large-Area Bifacial n-TOPCon Solar Cells with In Situ Phosphorus-Doped LPCVD-Based Poly-Si Passivating Contacts
Type: Visual
Date: Thursday, 9th September 2021
13:30 - 15:00
Author(s): M. Firat, H. Sivaramakrishnan Radhakrishnan, M. Recamán Payo, F. Duerinckx, L. Tous, P. Choulat, J. Poortmans
Presenter / Speaker: M. Firat, imec, Leuven, Belgium
Event: Conference Conference
Session: 2DV.3 Technologies for High Temperature Passivating Contacts and Homo Junction Silicon Solar Cells / Low Temperature Routes for Silico
Topic: 2. 2 High Temperature Route for Si Cells
Summary / Abstract: The potential of in situ phosphorus (P)-doping during low pressure chemical vapor deposition (LPCVD) is demonstrated for realizing polycrystalline silicon (poly-Si) films for contact passivation of Si solar cells. This method of fabrication was chosen, as it could simplify the production of industrial solar cells featuring poly-Si films, compared to the common approach relying on LPCVD of undoped poly-Si followed by an ex situ doping step. Passivating contacts consisting of the in situ doped poly-Si and thin silicon oxide (SiOx) films were integrated at the rear side of large-area bifacial n-type Tunnel Oxide Passivated Contact (n-TOPCon) solar cells with diffused emitter and screen-printed contacts. This resulted in power conversion efficiencies () up to 22.4% along with open circuit voltages (Voc) up to 693.7 mV, enabled by the poly-Si passivating contacts. Study of the properties of rear surface passivation of the cells revealed the excellent carrier selectivity of the passivating contacts with recombination current densities in passivated (J0,p,r) and metallized (J0,m,r) regions down to 3.6 fA/cm2 and 65.4 fA/cm2, respectively, and with a contact resistivity (c,r) of 1.7 mΩ∙cm2, on semi-textured surfaces.