We can’t literally see the congestion, but the electromagnetic spectrum has become so crowded with traffic at the frequencies commonly used for wireless connectivity and data communications, that data traffic jams are increasingly likely and disruptive. Compounding the problem is that today’s wireless devices and networks, operating at less than 6 GHz, are inherently inadequate for next-generation application requirements.
The solution is to make use of the millimeter-wave band of the spectrum (30 to 300 GHz), which offers much more bandwidth. The developing 5G standard you’ve heard so much about is intended to establish a common path forward for use of this so-called mmWave band.
However, it’s no mean feat to develop technology that can do this, especially for mobile applications. One issue is that ultra-high frequencies suffer from high propagation losses. That means high power output is required, but in a battery-powered device like a smartphone so is high energy efficiency – tough to do simultaneously. Another issue is that mmWave transmissions are susceptible to being blocked by buildings or other objects, and therefore the ability to form precise “pencil” beams that radiate to and from phased-array antennas is essential.
Enter GF’s 45nm RF SOI technology platform (45RFSOI), aimed at next-generation RF and mmWave applications like integrated front end modules (FEMs) and beamformers in 5G base stations and smartphones; broadband Satcom phased array terminals; automotive radar; and other evolving high-performance wired and wireless applications.
The 45RFSOI technology is fully qualified and ready for production, and we’re already working with major customers on several of these applications. We anticipate that several customers will begin to ramp products this year and next, and we expect the first volume production to commence later this year.
Process design kits are now available, and quarterly multiple-project wafer runs are also available for fast prototyping, so that customers can evaluate hardware results as early as possible.
The beauty of our 45RFSOI is that it’s an outgrowth of a 45nm partially depleted SOI server-class baseline 300mm technology that has been in volume production at multiple GF fabs for a decade. We evaluated it extensively for use in mmWave applications and added RF-centric enablement, device and technology features that give it the ability to meet forthcoming 5G requirements better than competing technologies.
For example, for superior RF performance the 45RFSOI platform combines high-frequency transistors (ft/fmax of 305/380 GHz, respectively) with a high-resistivity SOI substrate and RF-friendly metal interconnect. There are ultra-thick top-level copper interconnects for optimum transmission line design, and the interconnect also leads to improved noise isolation and suppression of harmonics so that extremely low-noise amplifiers (LNAs) can be achieved.
Meanwhile, to reduce power requirements, physical size and cost, 45RFSOI has been designed for the easy integration of features such as power amplifiers (PAs), switches, LNAs, phase shifters, up/down converters and voltage-controlled oscillators/phase-locked loops (VCOs/PLLs).
SOI technology electrically isolates the transistors from the substrate, unlike with standard CMOS technology where the substrate is a common node. Therefore, RF SOI transistors can be stacked to achieve higher breakdown voltages and power-handling capabilities, which is especially important for beamforming front-end circuits like PAs, LNAs and switches.
Moreover, because 45RFSOI enables such powerful and highly integrated chips, fewer chips will be required for an antenna array versus other technologies, giving customers the ability to build smaller, more cost-effective phased array systems.
A Range of RF Solutions
45RFSOI is the latest addition to GF’s set of technology solutions for RF applications, the industry’s broadest offering of RF foundry processes. They include 45RFSOI and 8SW RFSOI, silicon germanium (SiGe) and RF-CMOS technologies.
These technologies span a wide range of mature and advanced nodes with RF-optimized options, a broad range of ASIC design services and foundational intellectual property (IP).
Their most important feature, however, is that they help our customers address their difficult technological challenges, and give them the ability to better capitalize on the market opportunities before them.
mmWave Applications – Phased Array Antenna System