Plated Front Side Metallization on Transparent Conduction Oxide Utilizing Low-Cost APCVD SiO2 Insulating Layer

An important process step for galvanic metallization on transparent conducting oxide (TCO) is the preparation of a plating mask, which is an electrically insolating layer in the area where no metal deposition is desired. A polymer ink is often used for this purpose. A disadvantage, however, is that the front side of the solar cell is largely coated with polymer, hence large amounts of it must be recovered or, even worse, disposed of together with the solvents used in the later stripping process. To reduce costs, we take a different approach, namely screen-printing a polymer ink in the form of the later front metal grid, applying a full-area SiO2 coating at room temperature and lift off. This way we obtain a SiO2 instead of a polymer plating mask. At first glance, replacing polymer ink with SiO2 coating does not seem to be cost-effective. However, we have used a new atmospheric pressure chemical vapor deposition (APCVD) technology developed by us that potentially has very low investment and operating costs. In this work, we investigated this approach and demonstrated the performance of the SiO2 plating mask on heterojunction Si solar cells.