The quality of the silicon crystal determines the maximum achievable conversion efficiency of the final photovoltaic device. Thus, the quality control of the as-grown Si crystals is crucial to stabilize the manufacturing of modern Si solar cells. Semilab offers various solutions to control all the important material parameters in both multi- and monocrystalline silicon ingots.
Resistivity of the mono and multicrystalline ingots is tested by using eddy current sensor, integrated into various system platforms.
Metallic contamination and extended crystal defects are detected by using different versions of PhotoConductance Decay and Photoluminescence methods.
Finally, our Infrared Imaging system localizes the larger precipitations in the crystal in order to prevent the failures in the wire sawing process.
Photoluminescent Imaging is an excellent method for monitoring of multicrystalline, monocast or monocrystalline blocks. During the measurement, the laser illuminates the silicon block and the generated photoluminescent signal is detected by an IR camera. The illumination effects the recombination of charge carriers. If not, the defects are present and there is a chance of radiative recombination. During the radiative recombination, a photon is emitted which can be detected by an IR camera. PL intensity is inversely proportional to defect density and impurity concentration.
PLB measurement example - PL images
PLB measurement result example
PL image with the position of measured µ-PCD line (left), comparison of PL image pixel intensity and µ-PCD value at the same area (right)
Block photoluminescence imaging system for wafer and cell inspection is a fast and reliable solution for non-destructive quality measurement of silicon blocks.
PLB is fast, non-contact, easy-to-use system to detect defects and impurity concentration in silicon blocks for photovoltaic application.
Features and System specifications:
Ingot Imaging system: