March 31, 2025

Trends of Solar Silicon Wafer Size and Thickness for Different Cell Technologies

By Jun Chen, Gyou Seong Park, Øyvind Nielsen, RAAMS AS

Geopolitical challenges combined with the growing realization of the strategic importance of the solar photovoltaic (PV) industry have led to a trend of building regional value-chains for solar panel manufacturing.

Europe has stated a clear ambition to bring the PV industry back, which is one of the topics supported by the Diamonds4IF project.

The PV industry has been rapidly evolving with advancements in wafer size, wafer thickness, and solar cell technologies. These developments aim to optimize conversion efficiency, reduce costs, and meet the growing demand for renewable energy.

Companies with ambitions to build new manufacturing capacity in Europe need to understand these developments and reflect on their implications for choice of technology, equipment size, etc. This article explores the latest trends in silicon wafer size and thickness for different cell technologies, based on insights from recent industry reports and intelligence.

Wafer Thickness: Balancing Efficiency and Cost

Key Drivers and Limitations. The drive to reduce wafer thickness is primarily motivated by cost reduction. Technological limitations and efficiency considerations vary depending on cell technology:

  • PERC (Passivated Emitter and Rear Cell) (p-type):
    • Current mainstream wafer thickness: 150 to 160µm.
    • Limited potential for further thinning due to efficiency loss risks.
  • TOPCon (Tunnel Oxide Passivated Contact) (n-type):
    • Compatible with thinner wafers (130 to 150µm) due to its fully passivated rear structure, which also tolerates mechanical stress better.
    • Industry example: One large industry player ran 120 to 125µm wafers for months but reverted to 130µm.
  • HJT (Heterojunction cell Technology) (n-type):
    • Symmetrical structure and low-temperature cell process allow for even thinner wafers (100 to 130µm).
    • Challenge: High cracking rates.
  • IBC (Interdigitated Back Contact) (n-type):
    • Less sensitive to thickness variations but requires high-precision processing.
    • Likely to stay with 120 to 130µm wafers to avoid device efficiency degradation.
    • Intrinsic motivation for thinning is limited due to high process costs and niche market favoring maximum efficiency.

Feasibility of Ultra-Thin Wafers

  • R&D experiments by cell makers and wafer saw manufacturers have demonstrated that 100µm wafers are feasible for mass production, achieving over 90% yield under reduced cutting speeds.
  • Wafers thinner than 100µm, however, lack sufficient data to support their mass production feasibility.

Efficiency Considerations

  • For TOPCon, reducing thickness from 150 to 125µm has shown negligible efficiency loss (<0.02%) in some tests, attributed to process fluctuations rather than inherent limitations.
  • For HJT, theoretical absorption of over 90% visible light is achievable with 80µm wafers, but surface imperfections can lead to minor losses.

 

Wafer Size: The Shift Toward Larger Formats

Current Market Landscape. In 2024, the solar industry featured a variety of wafer sizes:

  • M6 (166mm):1% market share
  • M10 (182mm square wafers):23% market share.
  • M10 Near Rectangular (182×182mm to186mm): 30% market share.
  • M10R (182×199mm): 12% market share.
  • G12 (210mm square wafers):17% market share.
  • G12R (210×182mm):14% market share.
  • G12 half cut (210×105mm):3% market share.

Trend: G12 is steadily overtaking M10 as the preferred wafer format

  • Despite maintaining a significant presence in 2024, M10 and its extended formats are on a downward trend as the market shifts toward 210mm wafer formats.
  • M6, M10, and its extended formats will gradually lose market share and are expected to be phased out between 2026 and 2028.
  • G12 and its extended formats (G12 & G12R) are gradually replacing smaller wafer sizes and have strong potential to become the mainstream.

 

Full-Size versus Half-Cut Wafers. Solar cells are commonly cut in half after the cell process to reduce resistance losses in the module. There has been some demand to cut the Full-Size (pseudo-)square or rectangular wafers in half prior cell processing.

  • Full-Size Wafers:
    • Dominant in p-type and TOPCon cells.
    • Expected to remain mainstream for the next five years due to massive investments in TOPCon-compatible production lines.
  • Half-Cut Wafers:
    • Primarily used in HJT cells (g, 210×105mm format).
    • Market share tied to HJT adoption, which is projected to reach 20% by 2030.

Standardization and Transportation Efficiency

  • Modules made with G12R wafers adopt a format(2384mm×1134mm). that enables container space utilization of up to 98.5%, making it the most logistics-efficient option in the market.
  • This high level of transport efficiency not only reinforces its long-term viability but also contributes to lower shipping costs and improved overall economics.

Future Trends in Wafer Technology

G12 and G12R Wafers

  • G12 (210mm) and its rectangular variants are expected to play a significant role in the next five years.
  • Large investments in TOPCon production lines designed for G12 wafers ensure their continuity.

G13 Wafers

  • No significant movement toward G13 (230×230mm) wafers has been observed.
  • Transitioning to G13 would require costly upgrades to existing equipment, making it unlikely in the near/medium term.

 

The Role of Perovskite in Future Solar Technologies

Current Status

  • Perovskite solar cells account for only 0.2% of PV cell capacity, indicating early commercialization stages.
  • The world’s first GW-scale perovskite cell production line began mass production in 2025, but detailed specifications remain scarce.

Potential for Flexible Substrates

  • While perovskite cells could theoretically replace silicon in flexible substrates, widespread adoption is uncertain.
  • Tandem cells combining silicon and perovskite are considered the optimal configuration, with TOPCon emerging as a suitable bottom cell.

Efficiency Milestones

  • Laboratory results show tandem cells with TOPCon achieving efficiencies of 34 to 35%.
  • Existing TOPCon production capacity can be upgraded to support tandem cell manufacturing.

Conclusion

The solar industry has witnessed a recent dynamic transformation in wafer size and wafer thickness, driven by advancements in cell technologies like TOPCon, HJT, and IBC.

G12 in full formats (i.e, not half-cut at wafer level) remain dominant in the near/medium term, and Rectangular G12R wafers enhance logistics efficiency and cost-effectiveness through optimized container space utilization. Transitioning to G13 would require costly upgrades to existing equipment, making it unlikely in the near/medium term.

Meanwhile, the push for thinner wafers is gaining traction, especially for technologies like HJT.

Perovskite solar cells, though promising, are still in their infancy, with tandem configurations representing the most realistic path forward. As industry continues to innovate, these trends will shape the future of solar energy, balancing efficiency, cost, and scalability.

References

  • China Photovoltaic Industry Association, China PV Industry Development Roadmap 2024-2025 , February 27,
  • International Technology Roadmap for Photovoltaics (ITRPV), 15th Edition. May 2024.
  • InfoLink’s, 2024 global module shipment ranking: significant gap between tiers, February 18,
    [4] PwC. Energy New Era Series: Insights into Photovoltaic Industry Trends. Version 0.8, August 29, 2024.
  • Zhou, Bo. Ultra-Thin Silicon Wafers Help Reduce HJT Costs. Gaoce Co., September 2022.
  • Zhou, Ran. Perovskite & HJT Special In-Depth Report: New Technologies and Opportunities in Solar Cells. China Galaxy Securities, June 12, 2023, 13:57.
  • B&Y Consulting. Global and China Ultra-Thin N-Type Silicon Wafer Market Status and Future Development Trends, 2024–2030. December 3, 2024.
  • China Photovoltaic Industry Association (CPIA). T/CPIA 0003-2022: Technical Requirements for Dimensions and Mounting Holes of Crystalline Silicon PV Modules for Ground Installation. January 15, 2023.
  • China Business Industry Research Institute. 2025 Market Outlook and Forecast Report on China’s Perovskite Solar Cell Industry. December 2024.
  • Dong, Zitong. “Perovskite PV Technology Development Accelerates.” China Energy News, October 28, 2024, p.11.