IQE Introduces Customisable Silicon on Insulator (SOI) With Improved Thickness and Doping Control

10 October 2011

Cardiff, UK – 10 October 2011: IQE announces availability of ultrasmooth, customisable silicon on insulator (SOI) with improved thickness and doping control.
Since its introduction into main-stream manufacturing SOI has been integrated into a steadily growing number of applications. These include advanced microprocessors, high-voltage devices and complex MEMs and sensors. The significant electrostatic benefits of replacing bulk silicon wafers with SOI include reduction of parasitic device capacitance and resistance to latch-up. SOI also has very desirable mechanical properties e.g. provision of an excellent etch-stop at the interface between the silicon device layer and the buried oxide. This facilitates substrate removal for applications such as MEMS and sensors. SOI is manufactured using a variety of methods which include:

  • Hydrogen implanted layer transfer (HILT) where a layer of implanted hydrogen atoms produces a cleave plane below the surface of a donor wafer. This thin layer is then exfoliated from the donor wafer to an oxidised handle wafer and annealed. This method produces thin body SOI with excellent cross wafer thickness uniformity. However, it’s limited by the depth at which an implanter can form a cleave plane in the donor wafer. SOI wafers produced by this method have an upper thickness limit of between 1 – 2 ums. The range of available doping options is also typically limited.
  • Bond and etch-back involves directly bonding an oxidized silicon wafer with a second substrate. The majority of the second substrate is subsequently removed, by a combination of physical grinding and chemical etching to leave a thinner device layer. The major limitation of this method is the poor control of cross wafer uniformity which becomes more challenging as more of the device layer is removed.
  • Other methods include ELTRAN and SIMOX but these are not commonly used in high volume SOI manufacturing.

IQE Silicon Ltd is now able to offer a new range of SOI products and one of the few commercial opportunities that allows customers to tune the SOI parameters to their own specifications in terms of doping type and device layer thickness. We are also able to provide customised SOI in volumes from as little as 50 wafers for smaller, niche-driven applications.
Another important differentiator is that our SOI device layers are typically epitaxial silicon films which exhibits excellent crystal quality, improved gate oxide integrity and are COP (crystal originating particle) –free. Because we’re able to determine the structure of the device layer epitaxially, it is possible to have very tight control of the important film parameters whilst at the same time having the flexibility to produce structures which aren’t available using current SOI production methods. This includes SOI with multiple silicon layers with different doping or multiple layers of Si, Ge and SiGe alloys.
In order to address the issues highlighted by our customers IQE Silicon Compounds has launched its own SOI product range, offering high uniformity on both thin and thick device layers. We are also able to address the issue of SOI availability in small order quantities of between 50 and 500 wafers. The primary demand for SOI wafers is in 100mm, 150mm and 200mm wafer sizes and IQE can provide the complete range of products at these diameters.


Technical/Sales: IQE Silicon (+44 29 2083 9400) Rob Harper Moz Fisher
Press: IQE plc (+44 29 2083 9400) Chris Meadows

Note to Editors
IQE is the leading global supplier of advanced semiconductor wafers with products that cover a diverse range of applications, supported by an innovative outsourced foundry services portfolio that allows the Group to provide a 'one stop shop' for the wafer needs of the world's leading semiconductor manufacturers.
IQE uses advanced crystal growth technology (epitaxy) to manufacture and supply bespoke semiconductor wafers ('epi-wafers') to the major chip manufacturing companies, who then use these wafers to make the chips which form the key components of virtually all high technology systems. IQE is unique in being able to supply wafers using all of the leading crystal growth technology platforms.
IQE's products are found in many leading-edge consumer, communication, computing and industrial applications, including a complete range of wafer products for the wireless industry, such as mobile handsets and wireless infrastructure, Wi-Fi, WiMAX, base stations, GPS, and satellite communications; optical communications. The Group also manufactures advanced optoelectronic and photonic components such as semiconductor lasers, vertical cavity surface emitting lasers (VCSELs) and optical sensors for a wide range of applications including optical storage (CD, DVD, BluRay), thermal imaging, leading-edge medical products, pico-projection, finger navigation ultra high brightness LEDs, and high efficiency concentrator photovoltaic (CPV) solar cells.
The manufacturers of these chips are increasingly seeking to outsource wafer production to specialist foundries such as IQE in order to reduce overall wafer costs and accelerate time to market.
IQE also provides bespoke R&D services to deliver customised materials for specific applications and offers specialist technical staff to manufacture to specification either at its own facilities or on the customer's own sites. The Group is also able to leverage its global purchasing volumes to reduce the cost of raw materials. In this way, IQE's outsourced services, provide compelling benefits in terms of flexibility and predictability of cost, thereby significantly reducing operating risk.
IQE operates eight facilities located in Cardiff (two), Milton Keynes and Bath in the UK; in Bethlehem, Pennsylvania, Somerset, New Jersey and Spokane, Washington in the USA; and Singapore. The Group also has 11 sales offices located in major economic centres worldwide.