Abstract-In recent years, high-performance multicrystalline silicon (HPMC-Si) has emerged as an attractive alternative to traditional ingot-based multicrystalline silicon (mc-Si), with a similar cost structure but improved cell performance. Herein, we evaluate the gettering response of traditional mc-Si and HPMC-Si. Microanalytical techniques demonstrate that HPMC-Si and mc-Si share similar lifetime-limiting defect types but have different relative concentrations and distributions. HPMC-Si shows a substantial lifetime improvement after P-gettering compared with mc-Si, chiefly because of lower area fraction of dislocation-rich clusters. In both materials, the dislocation clusters and grain boundaries were associated with relatively higher interstitial iron point-defect concentrations after diffusion, which is suggestive of dissolving metal-impurity precipitates. The relatively fewer dislocation clusters in HPMC-Si are shown to exhibit similar characteristics to those found in mc-Si. Given similar governing principles, a proxy to determine relative recombination activity of dislocation clusters developed for mc-Si is successfully transferred to HPMC-Si. The lifetime in the remainder of HPMC-Si material is found to be limited by grain-boundary recombination. To reduce the recombination activity of grain boundaries in HPMC-Si, coordinated impurity control during growth, gettering, and passivation must be developed.

The current paper investigates the structure of low-lifetime areas observed in a < 110 >-oriented mono-like silicon ingot grown from monocrystalline seeds. These areas are related to dislocation clusters forming at seed junctions and several generation mechanisms are discussed. Dislocations generated due to physical contact between seeds could only be completely avoided by introducing gaps between the seeds. Large gaps were, however, found to suffer from alternative generation processes not found in small gaps. Dislocations generated in the seeds and in peripheral grains does not necessarily move in to the main crystal and low-lifetime areas are mainly related to dislocations generated above the seeding structure. Dislocations are found to form clusters aligning along < 111 >-directions and are proposed to happen by glide on {111}-planes from the boundary plane between two seed crystals. The extent of low-lifetime areas and corresponding dislocation clusters, for junctions containing no or small gaps, appear to mainly depend on the misorientation between seeds and by attaining sufficiently low misorientation the high bulk lifetime can be retained also at the junctions. Analysis of the misorientations along principal axes indicates that larger misorientations can be tolerated if the misorientation is limited to a single tilt axis

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Phone: þ47 92029610 $43% for the entire PV industry and 47%/37% for mono/ multi-Si respectively. However between 2010 and 2015, the period which has conclusively moved photovoltaics from a niche product to a cost efficient energy supply alternative in an increasing amount of markets, the CAGR of mono-Si has decreased to 18% while multi-Si remains above 40%.In contrast to mono-, multi-Si is by necessity a compromise: The generation of extended crystal defects cannot be eliminated. The ingots are made in square, thick walled crucibles, and using high purity quartz as in crucibles

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