SiGe

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For the company, see SiGe Semiconductor.

SiGe, or silicon-germanium, is the alloy of silicon and germanium. This semiconductor material is commonly used in the integrated circuit manufacturing industry, where it is employed for producing heterojunction bipolar transistors or as a strain-inducing layer for CMOS transistors. This relatively new technology offers interesting opportunities in mixed-signal circuit and analog circuit IC design and manufacture. Some of the key points of SiGe include:

SiGe is manufactured on conventional silicon wafers and leverages conventional silicon processing toolsets. By leveraging established silicon process equipment, SiGe processes achieve costs that are similar to silicon CMOS manufacturing versus other more expensive heterojunction technologies such as gallium arsenide.

SiGe allows state-of-the-art CMOS logic to be highly integrated with ultra high performance heterojunction bipolar transistors, making it optimal for mixed-signal circuits.

Heterojunction bipolar transistors have significantly higher forward gain and lower reverse gain which translates into better low current and high frequency performance than typically available from homojunction or traditional bipolar transistors

Being a heterojunction technology, the opportunity for band gap tuning exists which has normally been available only to compound semiconductors.

Recently, organogermanium precursors (e.g. isobutylgermane, alkylgermanium trichlorides, and dimethylaminogermanium trichloride) have been examined as less hazardous liquid alternatives to germane for MOVPE deposition of Ge-containing films such as high purity Ge, SiGe, and strained silicon.^[1]

The major players in SiGe foundry services include IBM, STMicroelectronics, TSMC, Freescale (originally Motorola Semiconductor), Sony, Atmel, Chartered Semiconductor, Micrel, Infineon, TI, IHP, and Jazz Semiconductor (originally Conexant). AMD disclosed a joint development with IBM for a SiGe stressed-silicon technology^[2], targeting the 65-nm process.

Silicon Germanium-on-insulator (SGOI) is a technology similar to the Silicon-On-Insulator (SOI) technology currently employed in today's computer chips. SGOI increases the speed of the transistors inside microchips by stretching the space between the atoms, which forces the electricity to travel faster.