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Undoped LPCVD PolySi Passivating Layer to Reduce Recombination Loss for Screen-Printed Contacts on Top of a Uniform Shallow Boron Emitter
X. Lu, M.K. Stodolny, B.W.H. van de Loo, P.R. Venema, J. Löffler
Silicon Materials and Cells
Subtopic: Homojunction Solar Cells
Event: 36th European Photovoltaic Solar Energy Conference and Exhibition
Session: 2BO.1.6
ISBN: 3-936338-60-4
0,00 EUR
Document(s): presentation


We present significant improvements of industrial fire-through screen printed contacts on Boron doped emitters by insertion of an oxide/intrinsic polysilicon (i-polySi) layer between the diffused homojunction emitter and the metal contact. The i-polySi is deposited in an LPCVD system simultaneously with rear polysilicon passivating layer. The main effect of this layer is a reduction of the contact recombination current density (Jo,c) from 1500-2000 fA/cm2 down to 500 fA/cm2, while it hardly affects the contact resistivity (c). Consequently, the implementation of this layer enabled cells with 6-7 mV higher Voc mainly due to reduced contact recombination. At the same time, pFF and FF increased by 1% absolute. Further work is ongoing to improve the industrial patterning process of polySi creating local i-polySi only below metal fingers.