Growth and Defects in Cast‐Mono Silicon for Solar Cells: A Review

Abstract

Cast‐mono silicon (CM‐Si) is a promising substrate to fabricate cost‐effective photovoltaic (PV) wafers used for solar cells with higher efficiency compared with conventional cast multicrystalline silicon (mc‐Si) due to its high throughput and good ingot quality. However, the unavoidable appearance of defects like dislocation, subgrain boundaries, impurities, multicrystallization, and twins, seriously limits its mass‐scale applications in the PV industry. In this review, the growth characteristics of the CM‐Si method are introduced first. Then, the attention is focused on the defects in CM‐Si. Other issues related to production costs that restrict the development of CM‐Si are also addressed in detail, such as seed cost and recycled seeds, n‐type CM‐Si, and large‐size CM‐Si. Finally, a conclusion is made and the prospects are given about the CM‐Si technique.

Attempt to correlate dislocations network and distribution to macroscale plane rotations in <001> cast-mono ingots

“…Ingots of various scales grown with the cast-mono process show that their edges are much more prone to defect multiplication with ingot height [6,14,17,20]. For this study, the ingot is chosen because it has been extensively characterized [14,15,17,18] and is representative of SGB multiplication along the height in side bricks which is an issue met and identified by industrials trying to develop cm-Si [21]. The cm-Si ingot used in this study is a 85 kg ingot grown with Cz seeds.…”

Theoretical models for large-sized crystal growth

“…The key devices supporting the third and fourth industrial revolutions are various semiconductor and optoelectronic devices, and the manufacturing of these devices is based on a variety of single crystals, such as monocrystalline silicon, 6 sapphire, 7 lithium niobate, 8,9 silicon carbide, 10 etc. In manufacturing engineering, the larger the size of a wafer, the lower the unit cost of each wafer.…”

Interplay between facetting and confinement in directional solidification of silicon: A direct comparison between experiments and phase-field simulations

“…During the solidification of silicon, crystal faceting and the associated twin formation are frequent and are reported in industrial ingots where the latter is the main mechanism of the grain structure formation. The corresponding facet dynamics, twin generation mechanisms and the interaction of both with other structural defects are of current interest [2][3][4][5][6]. Other main structural defects are dislocations that can be at the origin of subgrains known to be deleterious for photovoltaic properties and which interact with facets, twins and other defects in general [4,7].…”