Manuel Sellier, Product Marketing Manager at Soitec for the FD-SOI (and some other) SOI product lines has written an absolutely terrific primer entitled FD-SOI: A technology setting new standards for IoT, automotive and mobile connectivity applications. It’s in the August edition of the GSA Forum (the GSA is the Global Semiconductor Alliance).
If you know anyone who needs to quickly glean an understanding of FD-SOI that is both in-depth and broad, you’ll want to share this piece with them right away.
Before joining Soitec, Sellier was a chip designer at ST, where he gained deep experience designing FD-SOI chips. What’s more, he holds a Ph.D. in the modeling and circuit simulation of advanced MOS transistors, including FD-SOI and FinFETs. So, he really knows his stuff. But don’t worry that this might be too technical: Sellier’s writing is thoroughly accessible (and engaging!) for anyone in the industry.
He starts with the wafer history, then quickly moves on to the features from the designer’s standpoint. And he puts it all in a business perspective. I can’t recommend this piece enough – even if you think you know everything already yourself, you’re sure to learn something new.
Good news: there are far fewer bigoted extremists out there when it comes to FD-SOI vs. FinFETs. People want the best technology for their application. It’s that simple. That’s a key piece of news from the updated survey by Dan Hutcheson, CEO of VLSI Research, which he presented in the afternoon session of the SOI Consortium’s 2018 SOI Symposium in Silicon Valley
The afternoon then featured presentations by foundry partners, which I’ll cover here.
Also in the afternoon were presentations by wafer-maker Simgui, some innovative start-ups leveraging FD-SOI for custom SoCs and the final panel discussion. I’ll cover those in Part 3 of this series.
BTW, if somehow you missed my coverage of the morning sessions about very cool new products and projects from NXP, Sony, Audi, Airbus and Andes Technology, be sure to click here to read it.
The presentations are starting to be posted on the SOI Consortium Events page – but some won’t be. Either way, I’ll cover them here.
A couple years ago at the annual SOI Symposium in Silicon Valley, Dan Hutcheson presented results of a survey he did (ASN covered it – you can still read about it here). At the 2018 event, he presented an update, which is now posted. You can get it here.
The FD-SOI roadmap and IP availability are no longer issues for decision makers, he found. The 14nm branch – do you go FinFET or FD-SOI? – is gone. “Fins and FD are complementary,” he observed. Most people said they’d consider using both and running two roadmaps, choosing whichever technology is appropriate to a given design.
From a transistor viewpoint, the top reasons to choose FD-SOI is that it’s better for analog and has lower leakage/parastics. It’s perceived as better for complex, high mixed-signal SoCs, and especially for RF and sensor integration. In fact, people see RF as the new mixed-signal, wherein FD-SOI is uniquely positioned for 5G and mmWave.
From a business viewpoint, FD-SOI is perceived to have real advantages. In particular, FD-SOI wins when it comes to keeping down design costs, manufacturing costs and time-to-market. IoT is still the hottest target market for FD-SOI, to which he adds high growth expected in automotive and medical.
With 20 tape-outs in 2018, Samsung is seeing an acceleration in its FD-SOI business. “The trend is healthy,” said Hong Hoa, SVP of the company’s foundry business. FD-SOI, he continued, is on a “differentiation path.”
Samsung’s 28nm FD-SOI process, called 28FDS is at full maturity with very strong yields. They’re seeing more customers and a wider range of applications. The design infrastructure, silicon-verified IP and methodologies are also all mature. They have optimal implementation and verification guidelines for body bias design, a body bias memory usage guide, and a body bias generator integration guide. The process supports Grade 1 automotive, and will be qualified for Grade 2 in a few weeks.
FD-SOI, Hoa reminded the audience, offers superior RF performance compared to both planar bulk and 14nm FinFET. The Samsung strategy is to first provide a base for for the FD-SOI process, then add RF and eMRAM. The base for 28nm was done in 2016; they added RF in 2017 and eMRAM this year.
The Samsung platform for IoT applications integrates both RF and eMRAM to support multi-function needs in a single platform. Lead customers are already working with eMRAM in their designs, he added. (BTW, Samsung has a really nice video explaining their eMRAM offering – you can see it on YouTube here.)
The basic PDK for the Samsung 18nm FD-SOI process (18FDS) will be available in September 2018, with full production slated for fall of 2019. It will deliver a 24% increase in performance, a 38% decrease in power, and a 35% decrease in area for logic. RF for the 18FDSplatform will be ready by the end of this year, and eMRAM beginning in 2019.
With design wins from 36 customers underway, 12 of which are taping out in 22FDX (GF’s 22nm FD-SOI process) this year, the market has validated FDX for differentiation, said GF SVP Dr. Bami Bastani. And indeed, designers are using it for a wide array of applications across North America, Europe, Asia/Pacific and Japan.
Customers in the North America are designing in 22FDX for NB-IoT, industrial, RF/analog, mobile, network switches and cryptocurrency applications. In Europe, it’s more or less the same plus automotive/mmWave, optical transmission, wireless BTS and AI/ML. In Asia Pacific/Japan the mix is similar to Europe.
Bastani sees the three big enablers as the the strengths of the roadmap, the ecosystem and multi-sourcing from Dresden and Chengdu (where they’re already equipping the cleanrooms). He also tipped his hat in acknowledgment to the partnership with FD-SOI wafer supplier Soitec, noting that they have gone the extra mile to match GF’s requirements.
So that was the first part of a great afternoon. As mentioned above, my next post (part 3) will cover a very informative presentation by wafer-maker Simgui on the markets in China, plus talks by some innovative start-ups leveraging FD-SOI for custom SoCs and the final panel discussion.
Following the immense success of last year‘s FD-SOI training day in Silicon Valley, the SOI Consortium has another one planned for the end of April this year. If you want to start learning how to leverage FD-SOI in your chip designs, this is a great place to start. Click here for information on how to sign up.
ST Fellow Dr. Andreia Cathelin has put together another great line-up. World renowned professors and experts from industry will deliver a series of four training sections of 1.5 hours each, focused on energy efficient and low-power, low-voltage design techniques for analog, RF, high-speed, mmW and mixed-signal design.
You’ll learn about design techniques that take full advantage of the unique features of FD-SOI, including body biasing capabilities that further enhance the excellent analog/RF performances of these devices.
Each section of this training day will take you through concrete design examples that illustrate new implementation techniques enabled by FD-SOI technologies at the 28nm and 22nm nodes – and beyond.
The design examples will cover basic building blocks through SoC implementations. A global Q&A session will close the day.
Here’s a little more info on how the day will unfold. Click on the slides to see them in full screen.
FDSOI-specific design techniques for analog, RF and mmW applications – Andreia Cathelin, Fellow, STMicroelectronics
Andreia Cathelin is ST’s key design scientist for all advanced CMOS technologies, and is arguably the world’s leading expert on leveraging FD-SOI in high-performance, low-power RF/AMS SoCs. Her course will first present a very short overview of the major analog and RF technology features of 28nm FDSOI technology. Then the focus moves to the benefits of FD-SOI technology for analog/RF and millimeter-wave circuits. She’ll give design examples such as analog low-pass filters, inverter-based analog amplifiers and 30GHz and 60GHz Power Amplifiers, as well as mmW oscillators. There will be particular focus on the advantages of body biasing and special design techniques offering state-of-the-art performance.
Circuit Design Techniques in 22nm FD-SOI for 5G 28GHz Applications – Frank Zhang, Principal Member of Technical Staff, GlobalFoundries
Frank Zhang has designed chips using GF’s 22nm FD-SOI (22FDX) process for WLAN, 5G cellular and automotive radar applications. His course will focus on how to take advantages of FD-SOI’s high-frequency performance at relatively low-current density to design high performance RF/mmWave circuits. Examples circuits include a 28GHz LNA, a 28GHz PA and an RF switch for 5G applications. The FD-SOI advantages such as low capacitance, high breakdown voltage and high-output impedance will be exploited in these design examples. This course will also discuss how to extend these techniques to applications at higher frequencies and/or higher current densities that are subject to extreme temperatures and EM requirements.
Energy-Efficient Design in FDSOI – Bora Nikolic, Professor, UC Berkeley
Borivoje (“Bora”) Nikolić is known as one of the world’s top experts in body-biasing for digital logic (he and his team have designed more than ten chips in ST’s 28nm FD-SOI.) If you missed it, his team’s RISC-V chip was cited as one of Dr. Cathelin’s “Outstanding 28nm FD-SOI Chips Taped Out Through CMP” – read more about that here. His talk at the training day will present options for energy-efficient mixed-signal and digital design in FD-SOI technologies. He’ll explain how to generate body bias and use it to improve efficiency, with examples in RF and baseband building blocks, temperature sensors, data converters and voltage regulators. The techniques will be presented in the context of UC Berkeley’s latest RISC-V-based SoC, designed to operate in a very wide voltage range using 28nm FD-SOI.
mm-Wave and Fiber-Optics Design in FD-SOI CMOS Technologies – Sorin Voinigescu, Professor, University of Toronto
Sorin Voinigescu is a world renowned expert on millimeter-wave and 100+Gb/s ICs and atomic-scale semiconductor device technologies. His lecture will cover the main features of FD-SOI CMOS technology and how to efficiently use its unique features and suitable circuit topologies for mm-wave and broadband SoCs. He’ll begin with an overview of the impact of the back-gate bias and temperature on the measured I-V, transconductance, fT, and fMAX characteristics. Then he’ll compare the maximum available gain, MAG, of FDSOI MOSFETs with those of planar bulk CMOS and SiGe BiCMOS transistors through measurements up to 325 GHz. Next, he’ll provide biasing, sizing and step-by-step design examples for VCO, doubler, switches, PA, large swing optical modulator drivers and quasi-CML circuit topologies and layouts that make efficient use of the back-gate bias to overcome the limitations associated with the low breakdown voltage of 20nm and 12nm FD-SOI CMOS technologies.
With over 100 attendees filling every chair in the auditorium, last year’s training day was sold out. Although it was in Silicon Valley, people actually flew in from all over the world to be there. During the Q&A at the end, most everyone prefaced their questions by saying, “Thank you. I really learned a lot today.”
2018 will be no different – except that it’s sure to sell out even faster. Please note, though, that this is not a free event, so only the attendees will get copies of the slide decks.
Here’s key info you need to sign up. See you there!
When: 27 April 2018, 7:30am – 5pm.
Where: Crowne Plaza San Jose, Milpitas CA (parking is free)
Registration fee: US $485.00 (includes training book, breakfast, box lunch and refreshments during breaks)
How to sign up: Click here to go directly to the registration site.
Over a hundred chip designers packed the room for the SOI Consortium’s recent FD-SOI Design Techniques Tutorial Day. Five professors and scientists from top institutions covered design techniques with real examples in digital, mixed-signal, analog, RF, mmW and ULV memory.
Although it was in Silicon Valley, people actually flew in from all over the world to be there. During the Q&A at the end, most everyone prefaced their questions by saying, “Thank you. I really learned a lot today.”
Many of the questions pertained to body biasing, which prompted STMicroelectronics Fellow and Professor Andreia Cathelin to state what may well have been the take-away of the day. “Body biasing is not an obligation,” she said. “It’s an opportunity.”
The tutorial, sponsored by both Samsung and GlobalFoundries, was hosted by Samsung at their San Jose headquarters. But as this was a paying event, the presentations are only available to those who attended. Having had the good fortune to attend, I can give you a quick recap of some of the highlights.
Professor Cathelin set the stage with a basic overview of FD-SOI design for analog, mixed-signal and mmW.
FD-SOI is a perfect match for the many up and coming SOCs that are often half analog and/or RF and mmW. She explained how FD-SOI makes the analog designer’s life much easier (no small feat, since analog can seem rather like blackbox magic to those on the digital side). FD-SOI improves: performance (even at high frequencies), noise, short device efficiency and brings in a new very efficient transistor knob through the Vt (threshold voltage) tuning range. She also explained and gave numerous real examples implemented in ST’s 28FDSOI on how:
For mmW design, the transistor should operate at Lmin, and hence you get excellence performance in terms of both transition frequency (Ft – set by the technology node) and maximum frequency (Fmax – what the designer can really get in the gain vs. speed trade-off). This can be conjugated with the fact that the back-end of line, despite the very fine nm node, takes advantage of the SOI features and brings in very decent quality factors.
For mixed-signal/high-speed design, she showed how and why FD-SOI gives you improved variability, a fantastic switch performance, and reduced parasitic capacitance. All these permit state of the art results in high-speed data converters, or, for example, lower frequency implementations which do not need any specific calibration for best in class linearity and ENOB (effective number of bits).
She also presented details on the CEA-Leti electrical models which are now the reference stand point (Leti-UTSOI2) for any FDSOI technology, and are implemented in several industrial Design Kits such those from ST.
Next on tap was a very lively talk with almost 60 slides by Professor Sorin Voinigescu of U. Toronto. He focused on how to use the main features of FD-SOI for efficient design of RF, mm-wave and broadband fiber-optic SOCs. We’re talking high-speed/high-frequency here, and he had real examples of chips fabbed in ST’s 28FDSOI and some simulated in GlobalFoundries’ 22FDX technology.
He examined layout issues and gave measurement tips and tricks, noting that there are a lot of things you can do in FD-SOI that you can’t do in bulk. It’s also easier to get high linearity in FD-SOI – yet another reason that he really likes it. Plus he sees it as competitive in terms of scaling even past 7nm.
Professor Joachim Rodrigues of Lund University in Sweden (the largest university in Scandinavia) talked about Design Strategies for ULV memories in 28nm FD-SOI (ST’s FD-SOI technology). Noting that SRAMs eat a lot of area in an SOC, he first proposed a standard cell-based memory (SCM) in 28nm FD-SOI that cut memory area by 35% and reduced leakage by 70%.
He then talked about other chips he and his team have presented at the world’s top chip conferences, including an ultra-low voltage (ULV) SRAM. For that chip they lay claim to having the best write performance in ULV in sub-65nm (15MHz at 240mV), and the best performing read capability across all technologies (30MHz at 240mV). In each case, he explained the fundamental design considerations, concepts and trade-offs.
Professor Borivoje “Bora” Nikolic of UC Berkeley is an expert in body-biasing for digital logic. He and his team have designed ten chips in ST’s 28nm FD-SOI, and they’re now working on their 8th generation of energy-efficient SOCs. During his 90-slide (!) tutorial, Energy-Efficient Processors in 28nm FDSOI, he covered: digital logic (including implementation and adaptive tuning of cores for optimal energy efficiency); SRAM and caches (design scenarios and results compared to bulk); supply (generating, switching and analog assists); back bias (how it’s generated and how to use it). He finished with (60 slides of!) design examples and the results they got for power (including adaptive voltage scaling) and performance. He said to be on the lookout for upcoming publications on (even more!) chips, as well as new work on 22nm designs.
Even if you don’t know anything about mixed-signal design, you can walk away from an hour-long lecture by Professor Boris Murmann of Stanford with a good understanding of what it’s all about. In his talk, Pushing the Envelope in Mixed-Signal Design Using FD-SOI, he explained how a mixed-signal person thinks about FD-SOI, and how the different metrics and sweetspots vary depending on what you’re working on. From there it was the deep dive, as he got into the heart of his talk: simulated transition frequency vs. gm/lD. He explained that while some things might seem counter intuitive (like long channels are more efficient for very low Ft requirements), it’s all related to electrostatics. It’s not yet well explained in the literature, he said, but it should be a big deal. And he explained why with FD-SOI, you don’t have to design for the worst case. He then talked about where he sees things going – he sees a very bright future indeed for FD-SOI and analog as computing moves into very low-power neural networks. In the end, he said, it all boils down to the FD-SOI performance benefits with respect to better gate control. This translates into “significant improvements” for many mixed-signal/RF building blocks.
All in all, it was a really terrific day. BTW, this tutorial day followed a full-day FD-SOI Symposium in Silicon Valley. Click here to read about that.
ARM is stepping up its effort to support the FD-SOI ecosystem. “Yes, we’re back,” confirmed Ron Moore, VP of ARM’s physical design group. This and much more good news came out of the recent FD-SOI Symposium organized in Silicon Valley by the SOI Consortium.
The full-day Symposium played to a packed room, and was followed the next day by a full-day design tutorial. Though it was a Silicon Valley event, people flew in from all over the world to be there. (BTW, these symposia and tutorials will also be offered in Japan in June, and Shanghai in the fall). I’ll cover the Silicon Valley FD-SOI design tutorial (which was excellent, btw) in a separate post.
Most of the presentations are now posted on the SOI Consortium website. Here in this ASN post, I’ll touch on some of the highlights of the day. Then in upcoming posts I’ll cover the presentations from Samsung and GlobalFoundries.
If you’re designing in FD-SOI, we’ll help: that was the key message from ARM’s Ron Moore during the panel discussion at the end of the day. Earlier that morning, he’d given an excellent presentation entitled Low-Power IP: Essential Ingredients for IoT Opportunities.
CAGR for most IoT units is roughly 50%, he said, counting home (1.6B units by 2020), city (1.8B), industrial (0.6B) and automotive (1.1B). Compare that to the 2.8B smart phones – which he sees as a remote control and display device. The key differentiator for IoT is that 90% of the time the chip is idle, so you really don’t want leakage.
FD-SOI, he said, gives you a silicon platform that’s highly controllable, enables ultra-low power devices, and is really good with RF. ARM’s worked with Samsung’s 28FDS FD-SOI offering comparing libraries on bulk and FDSOI, for example, and came up with some impressive figures (see the picture below).
The foundry partners and wafer providers are in place. So now ARM is asking about which subsystems are needed to fuel FD-SOI adoption. Ron recognizes that the ARM IP portal doesn’t yet have anything posted for FD-SOI, but they know they need to do it. He called on the SOI Consortium to help with IoT reference designs and silicon proof points.
In the Q&A, audience member John Chen (VP of Technology and Foundry Management at NVIDIA) asked about FD-SOI and low-cost manufacturing of IoT chips. Moore replied that we should be integrating functionality and charging a premium for IoT chips – this is not about your 25-cent chip, he quipped.
Geoff Lees, SVP & GM of NXP’s Microcontroller business gave a terrific talk on their new i.MX 7 and 8 chips on 28nm FD-SOI. (And Rick Merritt gave it great coverage in EETimes – see NXP Shows First FD-SOI Chips.)
NXP’s been sampling the i.MX 7 ULP to customers over the last six months, the i.MX 8QM is ramping, and the i.MX 8QXP, 8Q and 8DX are enroute. Each of these chips is optimized for specific applications using biasing. A majority of the design of each chip is hard re-use, and the subsystems can be lifted and dropped right into the next chip in the series. Power consumption and leakage are a tiny fraction of what they’d had been in previous generations. Ultra low power (aka ULP) is heading to new levels, he says.
With FD-SOI, it’s easy to optimize at multiple points: in the chip design phase, in the production phase and in the use phase. They can meet a wide range of use cases, precisely targeting for power usage. FD-SOI makes it a win-win: it’s a very cost effective way to work for NXP, plus their customers today need that broader range of functionality from each chip.
Geoff tipped his hat to contributions made here by Professor Boris Murmann of Stanford, who’s driving mixed signal and RF into new areas, enabling high-performance analog and RF integration. (Folks attending the FD-SOI tutorial the next day had the good fortune to learn directly from Professor Murmann.)
Finally, he cited something recently pointed out by Soitec (they’re the SOI wafer folks) Chief Scientist Bich-Yen Nguyen: if half your chip is analog and/or RF, she’s observed, the future is very bright indeed for FD-SOI.
Briefly, here are some more highlights.
Synopsys: John Koeter, VP of the Marketing Solutions group showed slides of what they’ve done in terms of IP for Samsung and GlobalFoundries’ FD-SOI offerings. But there’s a lot they’ve done with partners he couldn’t show because it’s not public. In terms of tools and flows, it’s all straightforward.
Dreamchip: Designing their new chip in 22nm FD-SOI was 2.5x less expensive than designing it in FinFET would have been, said COO Jens Benndoorf in his presentation, New Computer Vision Processor Chip Design for Automotive ADAS CNN Applications in 22nm FDSOI. One application for these chips (which taped out in January) will be “digital mirroring”: replacing sideview mirrors with screens. Why hasn’t this been done before? Because LED flickering really messes with sensor readings – but they’ve mastered that with algorithms. The chip will also be used for 360o top view cameras and pedestrian detection. They’re using Arteris IP for the onchip networking, and implemented forward body bias (FBB). The reference platform they created for licensing has generated lots of interest in the automotive supply chain, he said.
Greenwaves: CEO Loic Lietar talked about the high performance, ultra-low power IoT applications processor they’re porting from bulk to FDSOI with a budget of just three million euros. The RISC-V chip leverages an open source architecture (which he says customers love) and targets smart city, smart factory, security and safety applications. As such, it needs to wake up very fast using just microwatts of power – a perfect match for body biasing in FD-SOI.
Leti: In her talk about roadmaps, CEO Marie-Noelle Semeria said the main two drivers they’re seeing in the move to FD-SOI are #1: low power (a customer making chips for hearing aids can cut power by 8x using body biasing, for example) and #2: RF (with Ft and Fmax performance that “…will be hard for FinFET to achieve”). Leti knows how to pull in all kinds of boosters, and is finding that RF performance is still excellent at the 10/7nm node. They’ve developed a low-power IoT platform with IP available for licensing. Other recent FD-SOI breakthroughs by Leti include: demonstration of a 5G mmW 60GHz transceiver developed with ST; the first 300mm Qbit, opening the door to quantum computing; a photodiode opening the door to a light-controlled SRAM; and a new 3D memory architecture leveraging their CoolCubeTM that they’re working on with Stanford.
IBS: CEO Handel Jones predicts that there “will be war in the year to come” at the 22nm node, as all the big foundries take aim. FD-SOI is the best technology for RF, ULP and AMS, and there’s a huge market for it. He also said China made the right decision to support FD-SOI, and will come out ahead in 5G.
The day ended with a lively panel discussion (moderated by yours truly) featuring experts from ARM, GF, Invecas, Soitec, Synopsys, Verisilicon and Sankalp. IP availability was a big theme, but generally there was agreement that while some gaps still exist, they’re being filled: lack of IP is no longer an issue. Soitec VP Christophe Maleville confirmed that the wafers for FD-SOI are readily available and that they’re seeing excellent yields.
All in all, it was another really good day for FD-SOI in Silicon Valley.
Would you like to better understand FDSOI-based chip design? If you’re in Silicon Valley, you’re in luck. On April 14th, the SOI Consortium is organizing a full day of FDSOI tutorials for chip designers. This is not a sales day. This is a learning day.
On the agenda are FD-SOI specific design techniques for: analog and RF integration (millimeter wave to high-speed wireline), ultra-low-power memories and microprocessor architecture, and finally energy-efficient digital and analog-mixed signal processing designs.
The courses will be given by top professors at top universities (including UC Berkeley, Stanford, U. Toronto and Lund). These folks not only know FDSOI inside and out, they’ve all spent many years working closely with industry, so they truly understand the challenges designers face. They’ve helped design real (and impressive) chips, and have stories to tell. (In fact, all of the chips they’ll be presenting were included in CMP’s multiproject wafer runs – click here if you want to see and read about some of them on CMP website.)
The FD-SOI Tutorial Day, which will be held in San Jose, will begin at 8am and run until 3pm. Each professor’s course will last one hour. Click here for registration information.
(The Tutorial Day follows the day after the annual SOI Silicon Valley Symposium in Santa Clara, which will be held on April 13th.)
Here’s a sneak peak at what the professors will be addressing during the FDSOI Tutorial Day.
If you know anything about FDSOI, you know ST’s been doing it longer than pretty much than anyone. Professor Cathelin will share her deep experience in designing ground-breaking chips.
She’ll start with a short overview of basic FDSOI design techniques and models, as well as the major analog and RF technology features of 28nm FDSOI technology. Then the focus shifts to the benefits of FD-SOI technology for analog/RF and millimeter-wave circuits, considering the full advantages of wide-voltage range tuning through body biasing. For each category of circuits (analog/RF and mmW), she’ll show concrete design examples such as an analog low-pass filter and a 60GHz Power Amplifier (an FDSOI-aware evolution of the one featured on the cover of Sedra/Smith’s Microelectronics Circuits 7th edition, which is probably on your bookshelf.) These will highlight the main design features specific to FD-SOI and offer silicon-proof of the resulting performance.
Particularly well-known for his work in millimeter wave and high-speed wireline design and modeling (which are central to IoT and 5G), Professor Voinigescu has worked with SOI-based technologies for over a decade. His course will cover how to efficiently use key features of FD-SOI CMOS technology in RF, mmW and broadband fiber-optic SoCs. He’ll first give an overview at the transistor level, presenting the impact of the back-gate bias on the measured I-V, transconductance, fT and fMAX characteristics. The maximum available power gain (MAG) of FDSOI MOSFETs will be compared with planar bulk CMOS and SiGe BiCMOS transistors through measurements up to 325 GHz.
Next, he’ll provide design examples including LNA, mixer, switches, CML logic and PA circuit topologies and layouts that make efficient use of the back-gate bias to overcome the limitations associated with the low breakdown voltage of sub-28nm CMOS technologies. Finally, he’ll look at a 60Gb/s large swing driver in 28nm FDSOI CMOS for a large extinction-ratio 44Gb/s SiPh MZM 3D-integrated module, as a practical demonstration of the unique capabilities of FDSOI technologies that cannot be realized in FinFET or planar bulk CMOS.
Having started his career as a digital ASIC process lead in the mobile group at Ericsson, Professor Rodrigues has a deep understanding of ultra-low power requirements. His tutorial will examine two different design strategies for ultra-low voltage (ULV) memories in 28nm FD-SOI.
For small storage capacities (below 4kb), he’ll cover the design of standard-cell based memories (SCM), which is based on a custom latch. Trade-offs for area cost, leakage power, access time, and access energy will be examined using different read logic styles. He’ll show how the full custom latch is seamlessly integrated in an RTL-GDSII design flow.
Next, he’ll cover the characteristics of a 28nm FD-SOI 128 kb ULV SRAM, based on a 7T bitcell with a single bitline. He’ll explain how the overall energy efficiency is enhanced by optimizations on all abstraction levels, from bitcell to macro integration. Degraded performance and reliability due to ULV operation is recovered by selectively overdriving the bitline and wordline with a new single-cycle charge-pump. A dedicated sense-amplifierless read architecture with a new address-decoding scheme delivers 90MHz read speed at 300mV, dissipating 8.4 fJ/bit-access. All performance data is silicon-proven.
Considered by his students at Berkeley as an “awesome” teacher, Professor Nikolic’s research activities include digital, analog and RF integrated circuit design and communications and signal processing systems. An expert in body-biasing, he’s now working on his 8th generation of energy-efficient SOCs. During the FDSOI tutorial, he’ll cover techniques specific to FDSOI design in detail, and present the design of a series of energy-efficient microprocessors. They are based on an open and free Berkeley RISC-V architecture and implement several techniques for operation in a very wide voltage range utilizing 28nm FDSOI. To enable agile dynamic voltage and frequency scaling with high energy efficiency, the designs feature an integrated switched-capacitor DC-DC converter. A custom-designed SRAM-based cache operates in a wide 0.45-1V supply range. Techniques that enable low-voltage SRAM operation include 8T cells, assist techniques and differential read.
If you’ve ever attended a talk by Professor Murmann, you know that he’s a really compelling speaker. His research interests are in the area of mixed-signal integrated circuit design, with special emphasis on data converters and sensor interfaces. In this course, he’ll look at how FD-SOI technology blends high integration density with outstanding analog device performance. In same-generation comparisons with bulk, he’ll review the specific advantages that FD-SOI brings to the design of mixed-signal blocks such as data converters and switched-capacitor blocks. Following the review of such general benchmarking data, he’ll show concrete design examples including an ultrasound interface circuit, a mixed-signal compute block, and a mixer-first RF front-end.
Dan Hutcheson, CEO of VLSIresearch, Inc. finally likes FD-SOI. That’s important, because he’s a really influential person in the chip world. Everybody who’s anybody in the chip biz pays attention to what VLSIresearch, Inc. has to say.
Dan recently gave a talk entitled “FD-SOI: Disruptive or Just Another Process?” to a packed-to-the-brim room during the FD-SOI Symposium in San Jose. (The ppt he used there is available on the SOI Consortium website – download it for free here).
Happily for those who didn’t make it to San Jose, Dan then went into the studio and made a video encore of his presentation for all to see – and it’s now posted on his weSRCH site. So you get not just his slides, but also his explanations and comments.
But for those of you who just want a quick recap, here are some of his key points.
Dan, as he’s always quick to point out, is an economist, albeit one extremely well-versed in chip technology. He always thought SOI was an elegant solution, but didn’t see cost savings in the fab as a driver. When asked to give a talk in San Jose, he decided to brush up a bit on what people were saying about FD-SOI. So he did an informal survey – and of course, being Dan, he can talk to just about anyone he wants.
In this case, he talked to decision makers from about a dozen top companies in the chip biz – enough to give him a 95% confidence level in his results. And the results are impressive: almost ¾ said they had FD-SOI designs underway or had already used it, while only about a third said they’ll stick firmly to bulk.
It turns out that there are companies out there doing both FinFETs and FD-SOI. Why? They’ve figured out the differentiable features, they told him. And some designers are now saying that FD-SOI is actually easier to design in than FinFETs, with one company reporting that design time in FD-SOI was half that of FinFETs.
Dan learned that the two biggest drivers of FD-SOI are IoT and automotive – IoT because those super power-stingy chips get enormous leverage out of back biasing, and automotive for reliability (and for both they get ease of analog integration).
But at the heart of it, it’s a business case: “It’s not about cost,” he says. “It’s about time-to-money.” With FD-SOI, TTM is significantly faster.
Those that go with FinFET are more often a big company (so they can afford the high NRE* costs) with a huge market, big die and a lot of digital. But if the market’s smaller, faster-moving and needs scaled-down NRE costs, then the people Dan talked to said they are turning to FD-SOI. They see it getting them to market faster, gives them lots of “knobs” and advantages in terms of power, reliability and analog integration, it’s easier to design in, and really enables product differentiation. In fact Dan had analog folks telling him that FD-SOI gave them back some of their favorite tricks and tools that they’d lost after the 130nm node.
Finally, Dan sees FD-SOI as a technology with both a long history and a long lifetime ahead. FD-SOI is not in itself disruptive, but is rather an enabler of disruption. The disruption, he says, is IoT. By all means check out his video if you want more detail on his perspective on IoT, automotive and the foundry offerings.
In conclusion, he urges users to strengthen the ecosystem’s momentum by disclosing their success stories – though he also sees how they might be reluctant to, as FD-SOI is the secret sauce that gives them a huge competitive advantage. But in the end rewards will be reaped, as driving volume up will drive costs down.
If you have a good FD-SOI design story you’d like to share, let us know here at ASN – we’ll be happy to consider it for publication, to help get the word around.
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*NRE = non-recurring engineering. In a fabless scenario, there are NRE for IP and design (engineering costs, up-front and royalty-based IP costs), NRE for masks and fabrication (mask costs, wafer prototype lots, tools costs, probe cards, load-boards and other one-time capital expenditures), and NRE for qualifications (ESD, latch-up and other industry-specific qualifications, as in automotives).
For this 3-part series, ASN spoke with Kelvin Low, senior director of marketing for Samsung Foundry and Axel Fischer, director of Samsung System LSI business in Europe about the company’s FD-SOI offering. Here in part 3, we’ll talk about the ecosystem. (In part 1 we talked about technology readiness, and in part 2, we talked about design.)
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ASN: Let’s talk a little more about IP availability.
Axel Fischer: The availability of IP is key for engaging these market segments. The technology itself is ready. The gating item often is the IP element.
Kelvin Low: The IP element is broadly ready. But we’re not stopping there. We’re enhancing the IP and adding on new suppliers. Most of them we can’t name yet just because of timing. But we can confidently say that multiple new IP suppliers are coming online, and many more have started to inquire about how they can get onboard.
ASN: In terms of the ecosystem, what remains to be done?
KL: The ecosystem can never end. Enhancements will always be welcome. More support – there are so many other EDA software companies out there available. We will enable them if there is a customer behind them. IP are dictated by the standards. As long as the product requires that, we’ll continue to look for partners to develop the IP.
KL: Back to one of the strategic decisions we made. We have immediately made available what ST Micro has in terms of IP portfolio to our customers. Then continuously build this ecosystem according to the new customers that we’re acquiring. ST Micro has developed these IPs for their own internal products, and they were gracious enough to allow these IPs to be opened up to be used by all customers without restriction.
As a group, as an ecosystem, we have to be more proactive in educating the market. What we’ve seen so far, whether it’s an initiative by Leti or an initiative by the SOI Consortium, these are very helpful. Now you have so many more knobs that you can play with, for designers we have to prepare all these PVT – which is process, voltage, temperature, and timing points so they can actually use it. It’s just a matter of preparation needed from our end, working with the ecosystem. The EDA tools must be optimized to make it as seamless, as transparent as possible.
ASN: Any closing thoughts?
KL: 28FDSOI is real. Samsung is committed. The technology is qualified already. The ecosystem is ready and expanding. This is working stuff. It’s not a powerpoint technology.
This is the last installment in ASN’s 3-part interview with Samsung on their 28nm FD-SOI foundry offering. If you missed the other parts, you can still read part 1 about technology readiness (click here), and part 2 on design considerations (click here).