Title:	Ultra-Thin ALD Grown Al2O3 Capped with SiNx Enabling iVoc Reaching 720 mV on Industrial p-Type Cz c-SI Wafers for PERC Solar Cells
Author(s):	G. Kökbudak, A.E. Keçeci, H. Nasser, M. Zolfaghari Borra, R. Turan
Topic:	Silicon Materials and Cells
Subtopic:	Manufacturing & Production of Si Cells
Event:	37th European Photovoltaic Solar Energy Conference and Exhibition
Session:	2CV.1.48
ISBN:	3-936338-73-6
Price:	0,00 EUR
Document(s):	poster

Abstract/Summary:

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Passivated emitter and rear contact (PERC) technology on p-type c-Si wafers is currently the dominant photovoltaic (PV) solar cell technology with more than 50% of current PV market share together with related PERT and PERL technologies [1]. Recently, ultra-high efficient mono-PERC cell has been demonstrated with an efficiency of 23.83% on p-type Cz c-Si wafers [2]. One of the outstanding profits of PERC technology over the standard Al-BSF cell is reduced rear surface recombination thanks to the rear passivation structure which minimizes the metal–silicon direct contact area. Al2O3/SiNx stack has come to be widely used rear passivation structure of the PERC cells. Thin films of Al2O3, usually deposited by atomic layer deposition (ALD), known to be excellent passivation candidates to suppress defects especially for p-type c-Si surfaces, are currently the most extensively explored, and implemented in PERC industry thanks to the superior chemical and field effect passivation Al2O3 affords [3], [4]. SiNx capping layer on Al2O3 commonly used as a barrier layer for rear metallization in addition to enhanced reflection from the rear side. In this work, we studied the passivation quality of symmetrically spatial ALD deposited and activated Al2O3 films capped by PECVD SiNx on p-type Cz-Si passivation structures as a function of the Al2O3 layer thickness before and after typical contact firing process.