PV Standards Activities Update – July 2011

By Kevin Nguyen, SEMI Standards Committee Manager

The SEMI Photovoltaic (PV) Standards Committee recently met at Intersolar North America in San Francisco, California. Eight of eleven balloted documents were approved by the committee, and will be published pending procedural review. A new standard on Specification for Silicon Wafers for Use as Photovoltaic Solar Cells was approved. This standard reflects current commercial practice in crystalline silicon PV Industry and will replace SEMI M6-1108 Specification for Silicon Wafers for Use as Photovoltaic Solar Cells.

Also, a new Test Method for Measuring Oxygen, Carbon, Boron and Phosphorus in Solar Silicon Wafers and Feedstock by Secondary Ion Mass Spectrometry was approved. SIMS (Secondary Ion Mass Spectrometry) test methods have been around for years and are published in SEMI for measuring impurities, e.g., MF1528 (Boron) and MF1366 (Oxygen). However, there was previously no test method for measuring Carbon and Phosphorus in polished silicon samples. This new standard will complement the recently published PV17-0611 Specification for Virgin Silicon Feedstock Materials for Photovoltaic Applications and pending Specification for Silicon Wafers for Use as Photovoltaic Solar Cells, which both reference SIMS as a technique for measuring oxygen, carbon, boron and phosphorus in solar silicon wafers and silicon feedstock.

In addition, five chemical standards — Hydrochloric Acid, Silane (SiH₄), Ammonia (NH₃), Hydrogen Selenide (H₂Se), Ammonium Hydroxide (NH₄OH), for PV applications — were approved. Including the eight previously published PV chemical standards, a total of thirteen SEMI chemicals standards for PV manufacturing will be available. Ballots for Hydrogen Peroxide, 2-Propanol, and Sulfuric Acid that were sent back to the SEMI PV Gases and Liquid Chemical Purity Standards Task Force for further rework due to technical rejects. Potassium Hydroxide (KOH) and Fluorine (F₂) are also being drafted by the task force.

Lastly, a highlight of the recent meetings was the formation of North America PV Materials Standards Committee (charter), co-chaired by David Williams (REC Group) and Lori Nye (Brewer Science). The SEMI International Standards Committee approved formation of this new committee in order to more effectively address the growing activity level in standardization of PV materials. By aligning with the Japan PV Materials Standards Committee, the new committee will avoid duplication of efforts. A counterpart European PV Materials Standards Committee is expected to form later this year.

How to Get Involved

If your company is not yet involved in these efforts to shape the future of PV, now is the perfect time to register. To learn more, please visit www.pvgroup.org/standards , or contact your local Standards staff. Participation in the SEMI Standards Program is free, but Standards Program registration is required.