Under CopyrightMack, SebastianSebastianMackKafle, BishalBishalKafleTessmann, ChristopherChristopherTessmannKrieg, KatrinKatrinKriegBashardoust, SattarSattarBashardoustLohmüller, ElmarElmarLohmüllerBelledin, UdoUdoBelledinSaint-Cast, PierrePierreSaint-CastHöffler, HannesHannesHöfflerOurinson, DanielDanielOurinsonFellmeth, TobiasTobiasFellmethSteinhauser, BerndBerndSteinhauserKluska, SvenSvenKluskaWolf, AndreasAndreasWolf2023-03-212023-03-212022Note-ID: 00009666https://publica.fraunhofer.de/handle/publica/437844https://doi.org/10.24406/publica-107710.4229/WCPEC-82022-1AO.6.310.24406/publica-1077This work reports on the status of industrial TOPCon solar cell development at Fraunhofer ISE. The baseline process makes use of Cz-Si:P wafers of M2 size, a TOPCon stack consisting of a thermal silicon oxide layer in combination with an 80 nm thin in-situ phosphorous-doped low-pressure chemical vapor deposited polysilicon layer as well as screen printed metal contacts. A comparison between different technologies for deposition of aluminum oxide (AlOx) layers reveals advantages for atomic layer deposition, which considerably reduces minority carrier surface recombination, and as a result leads to an overall increase in solar cell efficiency. Potential challenges in contacting by screen-printed and fired silver contacts, which might arise due to the presence of an AlOx layer on the rear side, are overcome by implementation of a laser-enhanced contact formation step, which reduces the series resistance of such solar cells by more than 2 Ωcm2. These modifications of our baseline process in combination with a new generation of metallization pastes allows for the fabrication of solar cells with a champion efficiency of 23.8%. Our stable baseline process allows for evaluation of other TOPCon-related technologies or plated contacts, as well as identifying challenges for so-called TOPCoRE solar cells.ensilicon solar cellTOPConTOPCoRE solar cellconference paper