March 28, 2025 By Arvind Narayanan Director, RF Product Line In the late 1980s and the early 90s, from the least expected places on earth in New York and Vermont, a quiet revolution in semiconductors was taking shape. One can’t fault even the nerdiest of all semiconductor enthusiasts for not paying attention because Moore’s law and the shrinking of silicon (Si) CMOS transistors were grabbing all the news and headlines. A group of engineers quietly rode the innovation wave and put the germanium (Ge) in Si bipolar junction transistors to deliver greatly improved device characteristics resulting in a promise for supreme RF and high-speed analog transistor performance. Their pioneering work using graded-Ge SiGe base transistors set the foundation for the commercial success of SiGe BiCMOS technologies on 8-inch wafers for various RF/Wireless and mmWave communications applications – the kind of success and the broad adoption that is rivalled only by a handful of semiconductor technologies like bulk CMOS, Gallium-Arsenide (GaAs) and RF Silicon-on-Insulator (SOI). While GF has been at the forefront of SOI technology innovation over the last 15 years, the legacy and the responsibility of being the torchbearer for SiGe BiCMOS technology advancement has been with GF’s (previously, IBM Microelectronics) technology developers and engineers for over four decades. Let’s trace down the history a bit more, relive and see what’s next in the story of SiGe, which the forefathers rightfully called “a story of persistence” [1]. GF SiGe History: A story where the sum of its parts is greater than the whole “A not so humble beginning” The first part of any series is usually the one that leaves a lasting impression, and GF’s first commercially successful SiGe technology fits the bill. More than a decade ago, the 0.35um SiGe BiCMOS technology [2] called SiGe5PAe set the stage for the entry of SiGe in the Wi-Fi power amplifier (PA) space just as the smartphone era was kicking off its world domination. This technology helped PA designers deliver the best combination of technical figure-of-merits (FoM) such as high output power, linearity and efficiency at the lowest cost. As demand for Wi-Fi grew and new Wi-Fi standards pushed for ever more stringent performance requirements, GF continued to deliver improvements on the base platform with various flavors of SiGe5PAXe and SiGe5PA4, including the high-resistivity substrate options that enabled full front-end ICs that integrated RF switches and Low-noise amplifiers (LNA) with a PA. Each flavor pushed the boundaries of Wi-Fi PA performance further by delivering improved PA performance while enhancing PA reliability and ruggedness for advanced WiFi standards. Table-1 shows the key features in GF’s 350nm SiGe BiCMOS technologies enabling the different applications and segments. What began as a humble endeavor turned out to be a huge commercial success with GF’s 0.35um SiGe technologies delivering seamless Wi-Fi experiences on high-end smartphones and tablets. Today, these technologies continue to dominate the PAs used in Wi-Fi Front-end-modules (FEM) in smartphones and have gained traction in Wireless Infrastructure applications such as PA pre-drivers. “One giant leap in Space and beyond” Usually, sequels are rarely better than the original story or series. But there are exceptions, such as GF’s 130nm SiGe technologies which are proof points for enabling several products and applications in both wireless and wired communications space [3] [4]. The high-frequency and high-voltage handling nature of SiGe heterojunction bipolar transistors (HBTs) in these technologies enables diverse applications such as mmWave and SATCOM PAs and LNAs, automotive radars, wireless backhaul and high-speed analog interface drivers. Specifically, GF’s SiGe8WL, SiGe8HP and SiGe8XP technologies pioneered the integration of high performance NPN transistors with high-quality mmWave and distributed passives such as transmission lines and microstrips that enabled the aforementioned applications. “When conquering space is not enough” In 2014, GF’s pioneering SiGe innovation led to the introduction of world’s first 90nm SiGe BiCMOS technology in SiGe9HP [5] which was followed with another industry-leading NPN performance enhancement via SiGe9HP+ [6]. Today, both these technologies combine to form one of the most comprehensive and competitive SiGe technologies available in the market. With advanced CMOS integration and a host of features including low-loss metallization and high-voltage LDMOS, the technology enabled state-of-the-art datacenter applications, such as transimpedance amplifiers (TIA) and drivers for high-speed optical communications, and other high-performance analog applications such as high-bandwidth analog to digital converters (ADCs) and terahertz imaging and sensing. “There is no endgame to revolution” With the advent of generative AI there is no lack of appetite for higher bandwidth, data rates or longer range for communications. At GF, after four decades of consistent innovation, we are once again ready for the next revolution in SiGe technologies serving the modern communication requirements. Recently, GF published the industry’s highest performing SiGe HBT with 415/600 GHz ft/fmax on a 45nm SOI platform [7] and is actively engaging with early customers on industry’s first-ever high-performance complementary 130nm SiGe BiCMOStechnology in 130CBIC via the Globalshuttle Multi-Project Wafer (MPW) program. The key features of 130CBIC enabling a broad set of applications are shown in Table-4. Looking into the future, one vector of growth could be increasing the ft/fmax of HBTs further to satisfy the advanced optical transceivers requirements for datacenter optical networks and generative AI applications. However, as GenAI seeps into smartphones, there is a logical need to lower power consumption or increase RF performance (lower-noise and higher gain) at the existing power levels for RF Front-end modules or related components. Also, as broadband internet access continues its march to far reaching corners of the globe, SiGe HBT performance and cost can be optimized for consumer satellite ground terminal applications helping connect the next 4 billion users to the internet. While CMOS hits the wall on Moore’s Law, the true potential of SiGe can be unlocked further and realized in much larger economies of scale for applications that demand unforgiving RF / high-speed performance and capabilities. To find out more about how GF’s SiGe technologies can support your next-generation RF and high-performance applications, you can contact us anytime through gf.com. Arvind Narayanan is the Director of Product Management with the RF Product Line at GlobalFoundries. He owns the SiGe and RF GaN strategic roadmap and manages the related portfolio of products. He has been with GlobalFoundries for over six years in various customer-facing roles. References: [1] D. L. Harame, B. S. Meyerson, “The Early History of IBM’s SiGe Mixed Signal Technology,” in IEEE Transactions on Electron Devices, Vol. 48, No. 11, November 2001. [2] A. Joseph et al., “A 0.35 gm SiGe BiCMOS Technology for Power Amplifier Applications”, IEEE BCTM 2007. [3] B. A. Orner et al., “A 0.13 µm BiCMOS technology featuring a 200/280 GHz (fT/fmax) SiGe HBT,” in Proc. IEEE Bipolar/BiCMOS Circuits and Technol. Meeting,2003, pp. 203-206 [4] P. Candra et al., “A 130nm sige bicmos technology for mm-wave applications featuring hbt with fT / fMAX of 260/320 ghz,” in IEEE RFIC Symposium, pp. 381–384, 2013 [5] J. J. Pekarik et al., “A 90nm SiGe BiCMOS technology for mm-wave and high-performance analog applications,” 2014 IEEE Bipolar/BiCMOS Circuits and Technology Meeting (BCTM), Coronado, CA, USA, 2014, pp. 92-95 [6] U. S. Raghunathan et al., “Performance Improvements of SiGe HBTs in 90nm BiCMOS Process with fT/fmax of 340/410 GHz,” 2022 IEEE BiCMOS and Compound Semiconductor Integrated Circuits and Technology Symposium (BCICTS), Phoenix, AZ, USA, 2022, pp. 232-235 [7] V. Jain et al., “415/610GHz fT/fMAX SiGe HBTs Integrated in a 45nm PDSOI BiCMOS process”, 2022 IEEE International Electron Devices Meeting (IEDM), pp. 266-268
