Expanding options for design with SiGe

When it comes to developing the highest performance, most reliable, yet cost-effective products for leading-edge applications, design engineers in the RF/microwave industry need and want options.

Traditionally, for high frequency applications 10 GHz and above, gallium arsenide (GaAs) has been considered the best overall material and technology to achieve the desired and required performance for next generation’s RF/microwave systems. With recent advances by compound semiconductor companies, however, enhancements to more traditional, high-volume silicon processes such as silicon germanium (SiGe) give design engineers expanded options to achieve their design goals.

A wide variety of SiGe products are available on the market today, including low noise amplifiers, medium power amplifiers, LO generators, wideband transistors, and variable gain amplifiers. Applications for SiGe products range from mobile platforms, personal navigation devices, AESA radars, satellite DBS/-VSAT, e-metering, software-defined radios (SDR), base stations, point-to-point radio links and WLAN, where high frequency and high integration levels are essential.

SiGe technology offers alternatives to GaAs by achieving comparable or better linearity, lower DC power consumption, immunity against out-of-band signals, spurious emission performance and comparable output power. Extensively tested and continually evolving to meet today’s system performance standards and demanding RF requirements, high-volume SiGe technology is widely deployed in the field and offers consistent parametric RF performance and reliability from wafer-to-wafer and lot-to-lot.

For example, we have developed a carbon-doped SiGe (SiGe:C) BiCMOS process (called QUBiC4xi)  that delivers high power gain, low noise figure and excellent dynamic range to address the industry’s growing demand for more options when it comes to high performance, reliable and highly integrated semiconductor devices. This technology is specifically designed to meet the needs of high-frequency applications up to 30 GHz in the wireless, broadband communications, networking and multimedia markets.

Engineers can select from two options from NXP. The first QUBiC4X is ideal for up to 30 GHz systems (Ft = 137 GHz) with 2.5 V breakdown voltage and ultra low noise applications (NF < 0.8 dB @ 10 GHz). Secondly, QUBiC4Xi, NXP's latest SiGe:C process, offers improved Ft (> 200 GHz) with 1.4 V breakdown voltage and even lower noise figure (NF < 0.5 dB @ 10 GHz) for applications beyond 30 GHz.

Engineers can now benefit from expanding options that offer GaAs-equivalent performance with numerous integration options of digital and high performance analog and RF functions, enabling more functionality into less space. Devices having smaller footprints also mean more competitive costs, and adding and increasing functionality on a single chip improves reliability, giving significant manufacturing advantages. Engineers also get all the benefits of silicon manufacturing, resulting in competitive cost, performance consistency and superb reliability to meet the demanding requirements of today’s leading-edge applications.

Greg Baker is a Sr. Director & Product Line Manager, RF Small Signal at NXP