Title:	Undoped LPCVD PolySi Passivating Layer to Reduce Recombination Loss for Screen-Printed Contacts on Top of a Uniform Shallow Boron Emitter
Author(s):	X. Lu, M.K. Stodolny, B.W.H. van de Loo, P.R. Venema, J. Löffler
Topic:	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
Price:	0,00 EUR
Document(s):	presentation

Abstract/Summary:

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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.