Coating Measurement of Solar Cells

Reflectance, Layer Thickness of Poly-Si Coating of TOPCon Solar Wafers

In the production of modern, highly efficient TOPCon solar cells, Poly-Si layers are deposited on the etched rear side of the solar wafers over an extremely thin tunnel oxide layer. Both the layer thickness and the processdependent optical constants of the Poly-Si layer determine the quality of the solar cells, especially the selective passivating contact on the rear side. The Helios-r8 inline and offline measuring systems are perfect instruments to analyze and optimize the coating process of your solar wafers with Poly-Si. It enables you to measure the layer thicknesses and the spectral optical constants n&k of the layers on the etched rear sides of the wafers. Because of its high measurement speed, the Helios-r8 is perfectly suited for inline measurements and homogeneity measurements of the Poly-Si layers, where several points on the wafer surface are measured.

The Helios-r8 systems are specifically designed for controlling poly-Si coatings on the rear side of TOPCon solar wafers. They provide precise measurements of layer thickness and optical constants (n&k), which are essential for ensuring high-quality selective backside passivation contacts. Available in inline or offline (manual or scan) versions, they provide fast and reliable results for production and laboratory use.

• Single-point measurement √
• Reflectance at user-definable wavelength √
• Coating layer thickness √
• User-definable quality limits √
• Good / Bad indication √
• Integrated fixed reference √
• Average Reflectance within a selectable wavelength interval √
• Manual single axis table √
• Automation full wafer mapping √