M1, M 2, M3, M4, M5, M6, M12 solar wafer and solar cell sizes
M1, M2, M3, M4, M5, M6 and M12 are standard different wafer sizes used in the solar cell production process
Why Wafer Size Matter?
The demand for wafers has exponentially increased over the past two decades due to the increase in the production and sale of PV systems, smartphones and more. The increase in the wafer size allows the production of more semiconductor instruments from only a single wafer, which improves productivity and effectiveness of wafers.
Thin Silicon Wafers Sizes
The wafer is the starting material in crystalline solar cells production, which is only about 200 µm thick. There have been many adjustments over the years with countless new wafer sizes appearing on the market.
Wafers were usually measured in inches but currently the millimeter measurement is used to describe the wafer size. Other custom Silicon wafer sizes depend on the company requirement.
History of Wafer Sizes
The first modules with a power class of 48 watts appeared in 1983, where 36 cells with 100 x 100 mm dimension were used. After that many cells with different dimensions were used, starting with 100 x 100 mm which were used in 1996. This cell size was available on the market until about 1996. Other dimensions like 125 x 125 mm then became the standard size for many years. This was then followed by wafer with the dimension of 156 mm, that has been defined as a standard for more than 10 years. For the 156 module size, the term “M0” wafer size then was defined.
Later this was successively replaced by the introduction of the 156.75 mm M2 variant. Without any increase in the overall dimensions of 60 cell module, M2 wafers can increase module power by more than 5Wp, which is a significant boost for a competitive cost per-watt, thus it became the mainstream and maintaining that status for several years. The move from 156mm x 156mm to the larger formats of 156.75mm x 156.75mm in mass production started in 2016. The old 6” format (156mm x 156mm) we all recognize is expected to disappear completely from the market by the end of 2019, according to the 2019 edition of the ITRPV survey.
Then the M3 variant, for example was again extended by 2 mm to a total size of 158.75 mm and the M4 wafer to 161.7 mm and was mainly used for n-Type bifacial modules.
At the end of another variant was launched on the market, which is the M6. The M6 has a wafer size of 166 mm and this results in a module size of 1776 x 1052 mm for the half-cell variant.
Market share of different Wafer Sizes
The M3 format is currently becoming the standard measure in the module range in Europe. Yet, other cell and module manufacturers still need to include the M6 variant in their portfolio in addition to the M2 and M3. Even now some companies are introducing the 210 mm variant, called M12. All efforts are being done to push high-efficiency products into the mainstream high-volume markets.