Solar modules or panels are typically composed of a set of solar cells wired together and encased in glass and framing. The cells are made by slicing purified “polysilicon” ingots into wafers and treating these with various thermal, chemical and coating processes to become the electricity-generating elements within the panels, which are seen on rooftops, streetlights and large-scale “solar farms” throughout the world.

During the fabrication of solar cells – from ingot to wafer to cell – certain chemicals, applied to create bulk chemical properties or to create certain layers in or on a silicon wafer, transform the ingots and wafers from inert substrates to energy-generating cells. The concentration, uniformity and other properties of these elements are critical to the finished cell’s electrical performance. To achieve their high electrical efficiencies, advanced solar cells require strict control of variations in these and other critical-to-quality treatments during manufacturing. Our products provide the means to measure these variations, understand their impact on production yield and throughput, and control or optimize production processes to reduce negative effects.

Within the overall solar product manufacturing industry, our customers are those who fabricate polysilicon ingots, wafers and advanced solar cells. These advanced cells lead the industry in the efficient conversion of light into electrical energy. They include those using Passivated Emitter and Rear Contact (PERC) technology, which have a specialized chemical layer on the back to increase light absorption, tunnel oxide passivated contact (TOPCon) technology, an evolved higher-efficiency design similar to PERC, and heterojunction technology (HJT) that involves multiple nano-scale chemical layer depositions on the top and bottom of the cell. These higher-power solar cells command a premium in the market compared to commodity-grade solar cells, providing their manufacturers with better profitability in this highly competitive industry.

Control and optimization of solar cell production starts with measurement. The PL Imaging equipment supplied by BT Imaging measures critical-to-quality material parameters related to the persistence of light-generated electrical charges and their ability to move through the material, both fundamentally important to finished cell efficiency and therefore power generation capacity.

Aurora’s DMTM products use proprietary patented technology, based on the principles of infrared spectroscopy, to measure the properties of the afore-mentioned solar cell chemical layers as they are deposited and annealed. Our VisualizeTM software then uses the real-time data provided by our DM measurement products to show the relationship between the per-wafer measurements and the changing spatial variations in chemical layer properties induced by variations in the behaviour of manufacturing equipment used to create these layers. This “MRI”-like view of process tool performance provides the means to quickly and effectively perform diagnostics, control and equipment optimization.

Our newest product, InsightTM, is a “data science” package that extends our product portfolio, from measurement and characterization of equipment variation, to provide a deep understanding of the effects of these variations on finished cell efficiency. This proprietary product analyses the large volume of data available from the sequence of finished solar cells in a production line and reveals the links between unwanted variations in their efficiency and the causes in production. These analyses allow advanced cell manufacturers to know precisely when and how to control their production for optimal yield and throughput, allowing them to increase their profits.

Decima - Model 3T - Inline Non-Contact Emitter Brochure