Major metallization paste producer Heraeus Photovoltaics has launched its first commercial product outside its solar cell metallization paste domain.
The company has targeted the multicrystalline silicon ingot manufacturing sector, accounting for more than 80% of the current wafer market with a high-purity SiO2 diffusion barrier coating dubbed HeraGlaze for enhanced crucible performance.
“HeraGlaze opens a new chapter in our roadmap as a technology leader and provides our customers with more added value,” noted Andreas Liebheit, President of Heraeus Photovoltaics. “It’s our first product beyond solar cell metallization and another R&D landmark, which enables our customers to realize further efficiency gains.”
HeraGlaze comes in a slurry form, which is applied on the porous surface of the crucibles carrying polysilicon chunks that are melted and formed into silicon ingots in a DSS furnace. This can be done directly at the production site of the customer.
HeraGlaze acts as a high-purity SiO2 diffusion barrier and prevents that thermally induced impurities such as iron that are transferred from the crucible into the silicon ingot during the melting and crystallization process. The higher wafer yield is achieved by increasing the usable section of a silicon ingot.
According to Heraeus Photovoltaics the wafer yield is increased by up to 4% and cell efficiency is improved by 0.1%. With an assumed an annual wafer production of 50GW today, the adoption of HeraGlaze would deliver close to an additional 2GW per year of ingot/wafer output without increasing wafer production capacity.
In recent years the multicrystalline wafer sector has come under increases pressure to reduce production costs and retain a competitive cost advantage over the resurgence of monocrystalline wafer production that has lower costs via larger area wafers and a host of production innovations to close the gap between the two wafer types.