Taking the strain

Silicon Genesis Corporation has successfully developed a new wafer-level strained substrate technology, called “Next-Generation Strain” or NGS.

NGS features uniaxial strain instead of biaxial strain and avoids the mobility degradation and the high defect levels associated with current silicon-germanium (SiGe) based biaxially strained silicon or strained silicon on insulator (s-SOI).

Several chip manufacturers, including Intel and Texas Instruments, have successfully demonstrated the significant benefits of uniaxial strain at the transistor level. Intel pioneered the use of uniaxial strain-enhanced transistor technology and is already using it in its 90nm process.

But until today, only local transistor-level uniaxial strain has been available. SiGen is changing that with the introduction of the NGS wafer-level strained substrate.

“This new material offers the potential for significant mobility enhancements over SiGe-based biaxial strain wafer technologies and is compatible with local straining approaches since the strains are additive. It also features very low defect levels due to SiGen’s use of its proprietary low-temperature processing technology. It can be directly integrated on silicon as an “epi-like” strained bulk wafer or on an insulator as a strained silicon-on-insulator wafer (s-SOI). The incremental production costs are expected to be significantly lower than biaxial technologies because it avoids the costly steps of growing and relaxing thick silicon-germanium layers,” said Francois J. Henley, President and CEO of Silicon Genesis.

“Uniaxial strain is now being recognised as the preferred strain type for deep-submicron device applications, and its local variant has displaced global biaxial strain as the mobility enhancer of choice,” added Dr. Scott Thompson, Associate Professor of the University of Florida’s Department of Electrical and Computer Engineering and former Intel Fellow Director of Intel’s 90nm Logic Technology and Strained Silicon Program.

“Biaxial strain has been plagued with process integration issues such as high defect levels and germanium interdiffusion, but more importantly is much less efficient in boosting PMOS transistor performance. Local uniaxial strain processes are already enhancing 90nm performance at many companies. The availability of a global uniaxially strained substrate can work with these existing approaches to substantially improve total transistor performance and has scaling advantages over local strain at the 45 nm node and beyond,” he added.

Silicon Genesis Corporation is actively pursuing the development and commercialisation of NGS with a number of partners.

For more information on the technology, click <link>here=http://www.sigen.com/ngsVer2.htm</link>.

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