Solar PV manufacturers have officially started efforts to establish a new ‘M10’ (182mm x 182mm p-type monocrystalline) large-area wafer size standard to reduce manufacturing costs throughout the related solar industry supply chain as the number of large-area wafer sizes have emerged in the last few years.
1. Material properties
Property | Specification | Inspection Method |
Growth method | CZ | -- |
Crystallinity | Monocrystalline Silicon | Preferential Etch Techniques（ASTM F47-88） |
Conductivity type | P-type | Napson EC-80TPN P/N tester |
Dopant | Boron/Gallium | -- |
Oxygen concentration [Oi] | ≤9E + 17 at/cm3 | FTIR (ASTM F121-83) |
Carbon Concentration [Cs] | ≤ 4E + 16 at/ cm3 | FTIR（ASTM F123-91） |
Etch pit density (dislocation density) | ≤ 500 cm-2 | Preferential Etch Techniques（ASTM F47-88） |
Surface orientation | <100> ±3° | X-ray Diffraction Method（ASTM F26-1987） |
Orientation of pseudo square sides | <010>, <001> ±3° | X-ray Diffraction Method（ASTM F26-1987） |
2. Electrical properties
Property | Specification | Inspection Method |
Resistivity | 0.4-1.5 Ω.cm | wafer inspection system |
MCLT (Minority carrier lifetime) | ≥50µs | Sinton BCT-400 QSSPC/Transient (with injection level: 1E15 cm-3) |
3. Geometry
Property | Specification | Inspection Method |
Geometry | pseudo square | -- |
Bevel edge shape | Round | -- |
Wafer Side length | 182±0.25 mm | wafer inspection system |
Wafer Diameter | φ247±0.25 mm | wafer inspection system |
Angle between adjacent sides | 90° ± 0.2° | wafer inspection system |
Thickness | 180﹢ 20/﹣10 µm 175﹢ 20/﹣10 µm 170﹢ 20/﹣10 µm 160﹢ 20/﹣10 µm 150﹢ 20/﹣10 µm Other | wafer inspection system |
TTV (Total thickness variation) | ≤ 28µm | wafer inspection system |
4. Surface properties
Property | Specification | Inspection Method |
Cutting method | Diamond wire saw | -- |
Surface quality | as cut and cleaned, no visible contamination, (oil or grease, finger prints, spot stains, epoxy/glue residue are not allowed) | wafer inspection system |
Saw marks | ≤ 15µm | wafer inspection system |
Bow | ≤ 40 µm | wafer inspection system |
Warp | ≤ 40 µm | wafer inspection system |
Chip | depth ≤0.3mm and length ≤ 0.5mm Max 2/pcs; no V-chip | Naked eyes or wafer inspection system |
Micro cracks / holes | Not allowed | wafer inspection system |
