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SOI wafers are commonly used semiconductor materials for leading edge devices such as low power and high speed LSI's, smart sensors, MEMS, and smart power devices. SEH has been providing several kinds of SOI wafers to meet various customers' requirements.

SEH started development of SOI wafers in 1988. We began with bonded SOI wafers by precisely controlled grinding and polishing technology, responding to customers' high quality requirements. We introduced Unibond® technology for thin SOI wafer production at low cost in 1997.

To meet customer demands for SOI layers in the 1.0 to 5.0 µm thickness range with excellent uniformity within wafer and wafer-to-wafer, SEH has optimized EPI growth on Unibond® SOI wafers. EPI on SOI can also be used to produce SOI stacks of dissimilar dopants and resistivity.

SOI Products from SEH:

Thick SOI Wafer (Bonded and Polished SOI with layer thickness > 1µm) Thin SOI Wafers (Unibond® SOI with layer thickness < 1µm)




SEH has a long history of SOI production. Our SOI facility in Nagano was established in 1988, and a new facility was built in 1997 to provide adequate capacity to support semiconductor customers and the developing micro-technology industry through at least 2010. SEH has the world's largest capacity for production of thick bonded SOI wafers, and we currently supply more than 50% of the SOI wafers used for semiconductor, MEMS, and MOEMS applications.

SEH's bonding and polishing process is similar to that being used by several other SOI manufacturers, but SEH has designed and developed it's own fabrication equipment that can produce the highest quality wafers for even the most demanding applications. SEH thick bonded SOI wafers feature a 0.8 mm edge terrace width that increases the chip yield on a wafer by up to 5% for a 5mm x 5 mm device.

A large inventory of finished SOI products is always available for customers who have an immediate need for research and development material, but our real strength lies in our ability to custom design SOI wafers for any customers needs. SEH's expertise as a manufacturer of low defect, annealed, or high resistivity crystal means that we can produce SOI wafers built with crystal that is also custom designed for the customer's application.

Optional ion implanted buried layers and the capability to manufacture multiple active layer structures make SEH the obvious choice for anyone looking for the latest technology and highest quality SOI wafers.

SOI Product Brochure
SOI for MEMS applications



Although SEH's thick bonding and polishing process produces wafers that are suitable for many semiconductor and MEMS applications, the limits of the polishing technology created a need for another process that could produce even thinner layers with even tighter layer thickness uniformity. SEH also offers a thin SOI Unibond® wafer manufactured with the SmartCut® process, which is licensed from Soitec.

In the thin bonding process, the active and handle wafers are bonded as in the thick bonding process, but the active wafer includes a hydrogen implanted layer. After bonding, the SOI wafer is annealed at moderate temperatures after which the bulk of the active layer separates from the bonded portion at the limit of the hydrogen implant. (See Figure 1.) Minimal additional processing is required to produce the final SOI wafer.

The SOI wafers produced by this process have very thin active layers with exceptional layer thickness uniformity. Thickness of 1000 nm and below are possible with a uniformity of <±5%. These wafers are of the highest quality with HF and Secco defect concentrations that are suitable for the most demanding semiconductor applications.

SEH's Unibond® process is now available for 200 mm and 300 mm wafers. Our new facility in Yokonodaira, Japan has adequate capacity to meet the needs of the semiconductor industry for the foreseeable future.

SOI Product B-rochure
SOI for MEMS applications