Higher yield of solar wafers and enhanced solar cell efficiency with new HeraGlaze© coating by Heraeus

Heraeus Photovoltaics, the worldwide leading supplier of metallization solutions to the PV industry, introduced HeraGlaze, a high-purity SiO2 diffusion barrier coating for enhanced crucible performance in wafer production. It is the first product of Heraeus Photovoltaics beyond metallization pastes and a leap in quality and yield for integrated PV-manufacturers. With HeraGlaze the wafer yield is increased by up to 4% and cell efficiency is improved by 0.1%. Assumed an annual wafer production of 50GW today, HeraGlaze will be able to deliver close to additional 2GW per year without increasing wafer production capacity.

HeraGlaze is used in the very first step of the of the solar cell manufacturing process, when poly-crystalline silicon blocks are melted into a single silicon ingot. This early process is crucial for the quality of the ingots and thus for the quality of the final product – the solar wafers.

The new product of Heraeus comes as a slurry, which is applied on the porous surface of the crucibles. This can be done directly at the production site of the customer and allows to retrofit or upgrade existing crucibles. As a result, the solution is very cost-efficient as no additional expenditures on new crucibles are required.

HeraGlaze acts as a barrier and prevents that thermally induced impurities such as iron are transferred from the crucible into the silicon ingot during the melting and crystallization of silicon. The higher wafer yield is achieved by increasing the usable section of a silicon ingot.

“HeraGlaze opens a new chapter in our roadmap as a technology leader and provides our customers with more added value. It’s our first product beyond solar cell metallization and another R&D landmark, which enables our customers to realize further efficiency gains,” says Andreas Liebheit, President of Heraeus Photovoltaics”.