Hinds Instruments and SolarWorld Lab collaborate on Publication

SolarWorld and Hinds collaborate to develop a birefringence measurement system for silicon ingots


Hillsboro, Oregon, September 25, 2013 – Hinds Instruments, a leading global supplier of birefringence measurement systems, along with SolarWorld Industries, also of Hillsboro, announced today the publication of an article describing a new instrument for the solar industry. The paper is entitled “Measuring stress in Si ingots using linear birefringence”. It describes a new system for evaluating the quality of silicon ingots early in the solar cell manufacturing process.

The authors on the paper include Bjoern Seipel, Ph.D. from SolarWorld Industries and Bob Wang, Ph.D. and Andy Leadbetter from Hinds Instruments. The work was originally presented as a poster at the Silicon PV Conference in Hamelin, Germany held on March 25-27, 2013. The associated paper was submitted and accepted for publication in the Proceedings of that meeting, Energy Procedia 38 (2013) 959-967.

Silicon ingots are one of the most significant cost drivers in the production of Si solar panels. Material losses occur throughout production, often due to stresses created during the crystal growing process. Ingot quality is essential to the solution: difficult to evaluate, but expensive to ignore. The sooner a manufacturer can identify defective material, the sooner they can correct the problem, and eliminate [link id=844]wasted material and processes. This new instrument offers the opportunity to assess stress in Si ingots at the beginning of the production process, before they are cut into wafers.

The Hinds Instruments Exicor® NIR Birefringence measurement system will provide this information. It is based on Hinds’ photoelastic modulator (PEM) technology. The Exicor system has been widely used since the late 1990s to evaluate stress birefringence in many different materials, including flat panel display glass, photomask blanks, plastics, lenses, and others. The instrument described in this paper is uniquely suited to studying silicon ingots because it has a near infrared light source that can be transmitted through the ingot and it has the handling capability to mechanically hold and scan a silicon ingot.

According to Dr. Seipel, “We believe this is a promising technique to detect stress in Si early in the solar cell fabrication process before subsequent processing costs are incurred.” Dr. Wang added, “We are excited to make what appears to be a significant contribution to this industry. The principle described in this paper will be deployed in different instrument configurations to benefit processes involving Si ingots made from different manufacturing processes and in different shapes.”

Hinds Instruments, Inc. is the world leader in developing and supplying polarization modulation technology for a broad range of applications. With 40+ years of polarization modulation experience, Hinds Instruments PEM-based solutions are proven tools for laboratory and research applications. Hinds’ family of products includes modulators, Stokes polarimeters, Mueller matrix polarimeters, MOKE measurement systems and Exicor® birefringence measurement systems. For more information, please contact Hinds Instruments.