D5.1 – IBC-HJT passivation test specifications

This document outlines the test specifications and process flow for evaluating passivation strategies in the context of the LEEMONS project, which aims to enhance photovoltaic (PV) efficiency using innovative nanostructured IBC-HJT cells. Initial trials will focus on 300 mm wafers processed at CEA-Leti, with subsequent passivation and characterisation steps carried out at CSEM. The goal is to limit potential lifetime degradation caused by the integration of nanostructures in M6 wafers and ensure compatibility with heterojunction architecture.
Key fabrication steps include ion implantation, annealing, cutting and passivation layer deposition. Several parameters will be investigated, such as implantation tilt (with a focus on 0°), the effect of native oxide removal and the use of hard masks for patterning. Special attention is given to the Levitor furnace at CEA and to other thermal processes including belt furnace testing at CSEM.
Characterisation methods involve ellipsometry, photoluminescence imaging, carrier lifetime measurements and heat mapping using a custom M6-format wafer with embedded thermocouples.
These techniques will help determine the origin of potential recombination issues. At least two experimental campaigns are planned, the first focused on establishing a baseline on 300 mm substrates and the second targeting optimisation on M6 wafers. Results will be documented in Deliverable D5.2 and will support further optimisation activities under Task 5.2.