Excellent Surface Passivation Quality on Crystalline Silicon Using Industrial‐Scale Direct‐Plasma TOPCon Deposition Technology. Issue 7 (16th April 2018)

• Record Type: Journal Article
• Authors: Steinhauser, Bernd; Polzin, Jana‐Isabelle; Feldmann, Frank; Hermle, Martin; Glunz, Stefan W.
• Is Part Of: Solar RRL. Volume 2:Issue 7(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-04-16
• Subjects: passivating contacts -- silicon solar cells -- surface passivation; Solar energy -- Periodicals; Photovoltaic power generation -- Periodicals; Solar energy -- Research -- Periodicals; Photovoltaic power generation -- Research -- Periodicals; Periodicals; 333.7923
• DOI: 10.1002/solr.201800068
• Languages: English
• ISSNs: 2367-198X

Abstract

Abstract : Passivating contacts based on a thin SiO x layer and a doped Si layer (TOPCon) are an appealing choice for pushing the efficiency of Si solar cells. One way to deposit the doped Si layer is to utilize radio‐frequency direct plasma‐enhanced chemical vapor deposition as commonly used in industry for the deposition of silicon nitride. However, due to the low operating frequency in the kHz range, there are concerns that ion bombardment might damage the thin SiO x layer and thus prevent suitable surface passivation. We demonstrate that this is not the case. Instead, the application of these layers on c‐Si results in excellent surface passivation. Minority carrier lifetimes exceeding the intrinsic bulk limit predicted by current models on 1 Ω cm n‐type were observed, out‐performing the reference layers. The excellent surface passivation results in an implied V OC of above 735 mV and an implied FF of almost 88% on 200 µm thick n‐type c‐Si. Furthermore, a lifetime test on 100 Ω cm n‐type c‐Si revealed an extraordinary lifetime of 190 ms (Δ n = 1 × 10 14 cm −3 ). Abstract : This work demonstrates that industrial‐grade direct‐plasma PECVD technology can be used to deposit TOPCon layers. The passivation is excellent and lifetimes exceeding the level predicted by the Richter Auger parameterization for 1 Ωcm n‐type are presented. The result is an implied open‐circuit voltage (i V OC ) of above 735 mV and an implied fill factor (iFF) of almost 88%. On 100 Ω cm n‐type c‐Si, a lifetime of 190 ms is reached.