Tag Archive UCL

ByAdele Hars

SEMI Honors RF-SOI Innovators Raskin & Aspar

RF-SOI innovators Jean-Pierre Raskin of UCL and Bernard Aspar of Soitec changed the course for key RF chips. The industry has long recognized their contributions: their solution for “trap-rich” RF-SOI wafers is now the starting point to virtually every FEM in every smart phone on the planet (really!). And of course here at ASN we’ve been following their work for over a decade. Now more accolades are coming in.

The latest is the 2017 European SEMI Award, which was given at ISS Europe 2018 for “…their seminal work with radio frequency silicon-on-insulator (RF-SOI) substrates” (read the press release here). As SEMI notes, the “…award winners’ pioneering research and collaboration with academia and industry led to major advances in RF switches and ushered RF-SOI technology from concept to worldwide adoption.” Aspar and Raskin were nominated and selected by their peers within the international semiconductor community.

Bernard Aspar, Executive Vice President, Communication & Power BU at Soitec
Aspar founded CEA-Leti spinoff Tracit Technologies in 2003. He was appointed senior vice president of the Tracit Division (now the Communication & Power business unit) when Soitec acquired Tracit in 2006. He has more than 15 years of experience in direct wafer-bonding and layer transfer. Aspar has filed more than 35 patents and co-authored some 100 scientific articles. He holds engineering and Ph.D. degrees in materials sciences and a master’s degree in microelectronics from the University of Montpellier, France.

Jean-Pierre Raskin, professor, Université catholique de Louvain (UCL)
Raskin contributed to pioneering scientific studies demonstrating that silicon-based MOS technology could enable affordable, high-quality mobile devices. His findings led to the advent of RF-SOI technology and today impact the global microelectronics industry. He is an IEEE Senior Member, EuMA Associate Member and Member of the Research Center in Micro and Nanoscopic Materials and Electronic Devices of the Université catholique de Louvain, where he has been a full professor since 2007. He is author or co-author of more than 350 scientific articles.

Their advanced RF-SOI technology is now behind a wide range of applications and systems in areas including mobile devices, satellite communications, IoT, automotive radar and aerospace.

If you want to better understand all this, a few years ago UCL and Soitec teams contributed an excellent article to ASN. It clearly explains how and why these new substrates came to be. You can still read it here. (Or if you’re still a little confused about RF-SOI vs. RF on FD-SOI, here’s a piece we did back in 2015 that explains the basics.)

ByAdele Hars

Outstanding 28nm FD-SOI Chips Taped Out Through CMP

ST Fellow Dr. Andreia Cathelin gave a terrific presentation at the recent CMP Annual Meeting. Now posted and freely available, Performance of Recent Outstanding 28nm FD-SOI Circuits Taped Out Through CMP highlighted eight examples – though she told ASN that she had easily over 50 from which to choose.

CMP is a Multi-Project Wafer (MPW) service organization in ICs, Photonic ICs and MEMS. They’ve been organizing prototyping and low volume production in cooperation with foundries for over 37 years. In partnership with ST since 1994, in the fall of 2012 they opened access to MPW runs in the 28nm FD-SOI process. More than 180 tape-outs have been fabricated since then using the process.

As Dr. Cathelin said, this lets ST show their industrial clients just how good the technology is. The chips she chose to cover in her presentation get “spectacular performance”, she said, especially for low-power or power-sensitive SoCs.

Here’s a quick recap of what she presented (some of which she co-authored), followed by some other SOI-related updates from the CMP meeting.

8 (of Many) Great Chips

FD-SOI, said Dr. Cathelin, “…is unmatched for cost-sensitive markets requiring digital and Mixed Signal SoC integration and performance.” In the first dozen slides of her presentation, she gave the technical details on the advantages of FD-SOI in  analog, RF/millimeter wave,  Analog/Mixed-Signal and digital design. If you’re a designer, you’ll want to check those out.

Then she ran through eight great chips – all manufactured by ST on 28nm FD-SOI through CMP’s MPW services. Here they are. (You can click on the illustrations to see them in full screen.)

1. A digital delay line with coarse/fine tuning through gate/body biasing in 28nm FDSOI

(Courtesy: CMP, ST, ISEN)

This chip was presented at ESSCIRC ’16 by a team from ISEN Lille, Professors Andreas Kaiser and Antoine Frappé (you can get the complete paper by I.Sourikopoulos et al on IEEE Xplore – click here.) As noted in the abstract, “Delay controllability has always been the major concern for the reliable implementation of circuits whose purpose is timing.” By leveraging body biasing in FD-SOI, this novel low-power design architecture for 60GHz receivers enables very high bandwidth together with fine-grain wide range delay flexibility, for implementing Delay Feedback Equalizer techniques in the Intermediate Frequency (IF) reception path. The results are state-of-the-art: ultra wide range, linear control, fs/mV sensitivity and energy efficient controllable delay cells.

2. 28FD-SOI Distributed Oscillator at 134 GHz and 202GHz

(Courtesy: CMP, ST, ims)

Presented at RFIC ’17 by a team from the IMS Bordeaux lab, Professor Yann Deval and STMicroelectronics, this chip demonstrates the highest oscillation frequency attainable so far at the 28nm node, be it planar bulk or FD-SOI. (Click here to get the full paper by R. Guillaume et al from IEEE Xplore.) As noted in the abstract, solutions on silicon for mmW and sub-mmW applications have been demonstrated for high-speed wireless communications, compact medical and security imaging. The main challenges are for the signal generation at high frequencies, and this implementation demonstrates spectacular oscillation frequencies close to the transistor’s transition frequency (fT). In this chip, they used body bias tuning to optimize the phase noise, demonstrated very low on-wafer variability, and simulation methods that permit measurement prediction precision within 0.1%.

3. A 128 kb Single-Bitline 8.4 fJ/bit 90MHz at 0.3V 7T Sense-Amplifier-less SRAM in 28nm FD-SOI

(Courtesy: CMP, ST, Lund U.)

Extremely energy efficient SoCs are key for the IoT era – but SRAM gets very tricky at ultra-low voltages (ULV). Presented at ESSCIRC ’16 by B. Mohammadi et al (on IEEE Xplore here) from Professor Joachim Rodrigues’ team at the Lund University, this is a 128 kb ULV SRAM, based on a 7T bitcell. The minimum operating voltage VMIN is measured as just 240mV and the retention voltage is as low as 200mV. FD-SOI enabled them to overcome ULV performance and reliability challenges by letting the Lund U.-lead team selectively overdrive the bitline and wordline with a new single-cycle charge-pump. Plus they came up with a new scheme so it doesn’t need a sense amplifier, yet delivered 90MHz read speed at 300mV, dissipating 8.4 fJ/bit-access.

4. Matched Ultrasound Receiver in 28FDSOI

(Courtesy: CMP, ST, Stanford U.)

Presented at ISSCC ’17 (with an extended relative paper at JSSC ’17) by M-C Chen et al with Professor Boris Murmann’s team at Stanford, the full title of the paper about this chip is A Pixel Pitch-Matched Ultrasound Receiver for 3-D Photoacoustic Imaging With Integrated Delta-Sigma Beamformer in 28-nm UTBB FD-SOI. (Click here to get it on IEEE Xplore.) It’s a a proof-of-concept for a big ultrasound receiver: a “pixel pitch-matched readout chip for 3-D photoacoustic (PA) imaging.” PA is “…an emerging medical imaging modality based on optical excitation and acoustic detection.” It’s used in studying cancer progression in clinical research, for example. As noted in the paper abstract, “The overall subarray beamforming approach improves the area per channel by 7.4 times and the single-channel SNR by 8 dB compared to prior art with similar delay resolution and power dissipation.” One of the (many) advantages of FD-SOI in this context is for front-end signal conditioning in each pixel. This unique type of pixel pitch-matched architecture implementation is possible only in a 28nm (or less) node of an FD-SOI technology, as it is matched with the pitch sizing needed for the ultrasound transducers in order to generate signals for a 3-D reading.

5. SleepTalker – 28nm FDSOI ULV WSN Transmitter: RF-mixed signal-digital SoC

(Courtesy: CMP, ST, UCL)

Presented at VLSI ’16 and JSSC ’17 by G. de Streel et al from Professor David Bol’s team at Université Catholique de Louvain la Neuve, the full title of the paper about this chip is SleepTalker: A ULV 802.15.4a IR-UWB Transmitter SoC in 28-nm FDSOI Achieving 14 pJ/b at 27 Mb/s With Channel Selection Based on Adaptive FBB and Digitally Programmable Pulse Shaping (get it on IEEE Xplore here). This chip tackles the IoT requirement for sensing functions that can operate in the ULV context. That means creating wireless sensor nodes (WSN) that can be powered on an energy harvesting power budget – and that’s a real challenge if you want to incorporate an RF component that can handle medium data rates (5-30 Mb/s) for vision or large distributed WSN networks. The energy efficiency has to be better than 100 pJ/b. To get there, the UCL-lead team used wide-range on-chip adaptive forward back biasing for “…threshold voltage reduction, PVT compensation, and tuning of both the carrier frequency and the output power. […] Operated at 0.55 V, it achieves a record energy efficiency of 14 pJ/b for the transmitter (TX) alone and 24 pJ/b for the complete SoC with embedded power management. The TX SoC occupies a core area of 0.93 mm2.”

6. A 128×8 Massive MIMO Precoder-Detector in 28FDSOI

(Courtesy: CMP, ST, Lund U.)

This massive MIMO chip was presented at ISSCC ’17 by a team from Professors Liang Liu and Ove Edforss at the Lund University  in a paper entitled 3.6 A 60pJ/b 300Mb/s 128×8 Massive MIMO precoder-detector in 28nm FD-SOI (H. Prabhu, et al; get it from IEEEE Xplore here). While Massive MIMO (MaMi) will be needed for next-gen communications, it can’t be achieved by just scaling MIMO – that would be too costly in terms of flexibility, area and power. As noted in the Lund U. team’s intro, “Algorithm optimizations and a highly flexible framework were evaluated on real measured channels. Extensive hardware time multiplexing lowered area cost, and leveraging on flexible FD-SOI body bias and clock gating resulted in an energy efficiency of 6.56nJ/QRD and 60pJ/b at 300Mb/s detection rate.”

7. ENVISION: A 0.26-to-10TOPS/W Subword-Parallel Dynamic-Voltage-Accuracy-Frequency-Scalable Convolutional Neural Network Processor in 28nm FDSOI

(Courtesy: CMP, ST, KU Leuven)

Today’s solutions for always-on visual recognition apps are an order of magnitude too power hungry for wearables. Running at 10’s to several 1OO’s of GOPS/W, they use classification algorithms called ConvNets, or Convolutional Neural Networks (CNN). The paper about this chip was presented at ISSCC ’17 by a team from professor Marian Verhelst at Katoliek Universiteit Leuven (B. Moons, et al, get it from IEEE Xplore here), and it changes everything. Leveraging FD-SOI and body-biasing, the KU Leuven team solved the power challenge with, “…the concept of hierarchical recognition processing, combined with the Envision platform: an energy-scalable ConvNet processor achieving efficiencies up to 10TOPS/W, while maintaining recognition rate and throughput. Envision hereby enables always-on visual recognition in wearable devices.”

8. Fine-Grained AVS in 28nm FDSOI Processor SoC

(Courtesy: CMP, ST, UC Berkeley)

As we learned at SOI Consortium FD-SOI Tutorial Day in SiValley last year, Professor Borivoje “Bora” Nikolic of UC Berkeley 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!) They presented the RISC-V chip here at ESSCIRC ’16 and JSSC ’17, in a paper entitled Sub-microsecond adaptive voltage scaling in a 28nm FD-SOI processor SoC (B.Keller, et al, on IEEE Xplore here). As they noted in the intro, a major challenge for mobile and IoT devices is that their workloads are highly variable, but they operate under very tight power budgets. If you apply adaptive voltage scaling (AVS), you can improve energy efficiency by scaling the voltage to match the workload. But in the current gen of SoCs, the AVS timescales of hundreds of microseconds is too slow. The chip the Berkeley team presented brought that down to sub-microseconds by aggressively applying body-biasing throughout the chip, including to workload measurement circuits and integrated power management units. The result is “… extremely fine-grained (<1μs) adaptive voltage scaling for mobile devices.” (BTW, they expand on some of the details in another paper published in 2017.)  These design techniques are now taught at UC Berkeley, as this kind of implementation is the subject of a course in SoC design (including the RF part of transceivers); a first educational chip has already been taped-out and successfully measured. (BTW, Professor Nikolic will once again join Dr. Cathelin and other luminaries in teaching at the SOI Consortium’s FD-SOI Training Day in Silicon Valley, 27 April 2018 –  click here for sign-up information.)

More SOI Through CMP

At the meeting, CMP also made a presentation on all their MPW offerings – you can get it here. On ST’s SOI (in addition to 28nm FD-SOI, of course), that includes the new 160nm SOIBCD8s: Bipolar-CMOS-DMOS Smart Power (for automotive sensor interface ICs, 3D ultrasound, MEMS & micro-mirror drivers); and 130nm H9-SOI-FEM: Front-End Module (for radio receiver/transceiver, cellular, WiFi, and automotive keyless systems).

CMP also provides tutorials that are used by institutions across the globe. A new update to the tutorial, RTL to GDS Digital Design Flow in 28nm FD-SOI Process is now available – you can see the presentation they did about that here. (It now includes LVS and DRC steps with Mentor/Calibre or Cadence/PVS.) Other services, like the 2-day, hands-on THINGS2DO FD-SOI training days at the end of March are always fully booked almost immediately, but don’t hesitate to inquire, as they’ll be adding more.

For some more examples of 28nm FD-SOI chips run through CMP over the years, see their website pages on Examples of Manufactured ICs. There are also some nice examples on pages 21 and 23 of their most recent annual report.

For those in the photonics world, CMP has teamed up with Leti to offer Si-310 PHMP2M, a 200mm CMOS SOI platform. CMP is cooperating with Tyndall for the photonics packaging – see that presentation here.  Training kits and tutorials will be available in Q3 of this year.

And in partnership with MEMSCAP, CMP offers Multi-User MEMS Processes (aka MUMPs) for SOI-MEMS.

So lots of terrific SOI resources for CMP – check it out!

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Note: special thanks to Andreia Cathelin of ST and Kholdoun Torki of CMP for their help on this piece.

ByAdele Hars

RFSOI Short Course – Great Line-Up! (EuroSOI, March 2018)

RF-SOI is in every smart phone out there, and with 5G, there are lots more applications on the horizon. If you’d like to learn more about designing in RF-SOI, there’s a great short course coming up the day before and in conjunction with the EuroSOI-ULIS Conference in Granada, Spain.

The title of this short course is RFSOI: from basics to practical use of wireless technology. Program and registration details can be found here. The course runs for the full day on Sunday, 18 March 2018.

The talks, which are being given by a stellar line-up of experts, include:

  • RF SOI, fabrication, materials and eco-system – Ionut Radu Director of Advanced R&D, Soitec
  • Fundamentals of RF SOI technology – Jean-Pierre Raskin, Professor, UCL
  • 22nm FDSOI Technology optimized for RF/mmWave Applications – David L. Harame, RF CTO Development and Enablement, GlobalFoundries
  • RF SOI technology and components for 5G connectivity – Christine Raynaud, Program Manager (Business Development – Technology to Design), CEA-Leti
  • Analog and RF design on SOI – Barend van Liempd, Senior Researcher, imec
  • Techniques and tricks for RF measurements on SOI – Andrej Rumiantsev, Director RF Technologies, MPI Corporation
  • FOSS TCAD/EDA tools for advanced SOI-device modeling – Wladek Grabinski, R&D CM Manager, MOS-AK
  • RF design flow for SOI – Ian Dennison, Design Systems Senior Group Director, Cadence

The course is being organized by SOI Consortium members Incize and Soitec.

BTW, this year marks the 4th joint EUROSOI – ULIS Conference. The EuroSOI Conference, which has been ongoing for decades, is well paired with the ULtimate Integration on Silicon Conference. The joint conference provides an interactive forum for scientists and engineers working in the field of SOI technology and advanced nanoscale devices. One of the key objectives is to promote collaboration and partnership between different players from academia, research and industry. As such, it covers technical topics, industry trends and updates from pertinent European programs.

EuroSOI-ULIS will take place 19–21 March 2018 at the University of Granada in Spain. For information on the program and how to register, see the website. Following the conference, the papers will be available at the IEEE Xplore® digital library, and the best papers will be published in a special issue of Solid-State Electronics.




ByGianni PRATA

RF-SOI Innovator JP Raskin (his team’s work is in your smartphone) Awarded Blondel Medal


Professor Jean-Pierre Raskin (right) receiving the Blondel Medal for his industry-changing work on RF-SOI. Jury president Professor Pere Rocal I Cabarrocas (left) of the Ecole Polytechnique – Université Paris-Saclay presented the prize.

RF-SOI substrate guru Jean-Pierre Raskin, whose team at UCL* has driven the technology behind the most advanced wafer substrates for RF applications, has been awarded one of the highest honors in electronics: the prestigious Blondel Medal. The technology he pioneered is now in virtually all the world’s smartphones, and used by just about every RF foundry on the planet.

Dr. Raskin’s team first demonstrated a radical new approach (dubbed “trap rich” at the time) for improving the RF performance of high-resistivity (HR) SOI substrates back in 2003. Teams from UCL and Soitec then worked together on the industrialization, making it commercially available in SOI substrates for RF applications.

ASN readers will recognize this work from a 2013 article Dr. Raskin co-authored, Soitec and UCL Boost the RF Performance of SOI Substrates.

The result was a new wafer substrate Soitec named eSI, for enhanced Signal Integrity, and it’s been wildly successful. In fact Soitec estimates that more than one billion RF devices are produced each quarter using their eSI wafers. It’s been used for 2G, 3G and now 4G and LTE. With the advent of LTE-Advanced (aka LTE-A), 5G and Wi-Fi 802.11.ac (aka Gigabit Wi-Fi), the latest iterations of the Raskin team’s technology are in Soitec’s most advanced eSI90 wafers.

The Blondel Medal is the highest honor awarded by the SEE (the French Society for Electricity, Electronics, IT and Communications Technologies). It recognizes a researcher under 45 years old who has authored works or recorded exceptional achievements that have contributed to the advancement of science in Information and Communication Technology.

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*UCL is the Université catholique de Louvain in Belgium. Click here to read more about Dr. Raskin’s research group.

ByFanny Rodriguez

Great line-up planned for IEEE S3S (SOI, 3D and low-voltage — 5-8 October, Sonoma, CA). Advance Program available. Registration still open.


Now in its third year, the 2015 IEEE S3S Conference has evolved into the premier venue for sharing the latest and most important findings in the areas of process integration, advanced materials & materials processing, and device and circuit design for SOI, 3D and low-voltage microelectronics. World-class leading experts in their fields will come to this year’s S3S Conference to present, discuss and debate the most recent breakthroughs in their research.

This year’s program includes:


The conference also features several events tailored for socialization and peer-to-peer discussions, such as the welcome reception, the cookout and the interactive Poster & Reception Session which is a great place to meet new colleagues and learn and exchange insights on technical topics. Enjoy a light snack and a beverage of your choice while meandering around to meet and discuss technical issues with long-time colleagues and make connections with new and influential experts and decision makers in your field.

Take time to visit the local attractions of Sonoma County. Sonoma is well known for outdoor recreation, spas, golf, night life, shopping, culinary activities, arts and music and wineries. It is truly my pleasure to serve as the General Chair of the 2015 Conference. —Bruce Doris

Download the Advance Program

Find all the details about the conference on our website: s3sconference

Click here to go directly to the IEEE S3S Conference registration page.

Click here for hotel information. To be sure of getting a room at the special conference rate book before 18 September 2015.

S3S Conference

The DoubleTree by Hilton Sonoma Wine Country, One Doubletree Drive, Rohnert Park, CA 94928

October 5th thru 8th, 2015

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LIgroupS3SJoin the IEEE S3S Conference group on LinkedIn to follow the news — click here or search on LinkedIn for IEEE S3S.

ByGianni PRATA

GF, NXP, Infineon and more at SOI Workshop During Silicon Saxony Day (Dresden, 7 July 2015)


Silicon Europe (an alliance of Europe’s leading micro- and nanoelectronics clusters) and the SOI Consortium have organized an SOI Workshop on the 7th of July 2015, during the 10th Silicon Saxony Day in Dresden.

Here’s the agenda:

  • Quick Introduction
  • More than Moore Market Analysis and Opportunities (Yole)
  • Power SOI and applications (NXP)
  • Foundry offer (GlobalFoundries)
  • FD-SOI status review (Giorgio Cesana, SOI Consortium)
  • Analog/RF, sensors and MEMS in SOI: demos and performance assessment (Denis Flandre, UCL)
  • Automotive IC needs (Infineon)

The workshop, which runs from 1:30 – 4:30, will be held in English. There is an entry fee (waived for students) for Silicon Saxony Day, but once you’re in, the SOI Workshop is free.


RF-SOI: Already in Every Smartphone, New Opps Abound in IoT (SF Workshop Part 3 of 3: IBM, ST, GF and more)

RF-SOI is already found in virtually every new smartphone out there, so the RF-SOI session of the recent FD-SOI/RF-SOI Workshop in San Francisco focused on long-term growth and further opportunities.

In case you missed it, ASN already covered the SF Workshop’s FD-SOI presentations (Samsung, ST and the EDA houses – click here for that post) and the panel discussion (where we learned Cisco is working on an FD-SOI chip – click here to read that post). As we mentioned there, the workshop was a huge success, with over 150 people from over 80 companies in the audience.

The presentations are becoming available on the SOI Consortium website, so keep checking there. (Also, if you want to know more about how the special wafers for RF-SOI solve design challenges, Soitec contributed an excellent ASN article a couple years ago – click here to read it.) But for now, here’s a brief recap of the RF-SOI presentations.


IBM has been offering RF-SOI foundry services since 2007 and recently said it shipped more than 7 billion RF-SOI chips in the last 3 years (read more about that here). Clearly they are experts in this business. In his talk, RF-SOI: Redefining Mobility and More in the Front-End, Mark Ireland, VP of Strategy and Business Development, Microelectronics Division, IBM Systems & Technology Group, said that LTE is the fastest developing mobile system technology ever. A big driver is mobile video: the CAGR there is 66% over the next five years, and it’s happening on both high-end and low-end smartphones.



Next comes IoT as an RF-SOI driver, and he gave a roadmap and examples.


He also looked at demand for RF-SOI wafers, which are typically 200mm, but he noted that 300mm is starting to sustain growth, too.


(You might also want to also refer to the IBM RF-SOI presentations given recently in Shanghai and Tokyo.)


In her presentation entitled, ST H9SOI_FEM: 0.13µm RF-SOI Technology for Front End Module Integration, Laura Formenti, Infrastructure and RF-SOI BU Director, STMicroelectronics focused on front-end module (FEM) integration (ST contributed an excellent article on this to ASN last summer – you can read it here). She made the link between new opportunities in RF-SOI and new developments by Soitec in RF-SOI wafers.


Putting power amplifiers (PA) on RF-SOI is starting to happen, and she provided data showing that they’re now closing in on GaAs in terms of performance.


ST is offering H9SOI_FEM on a foundry basis and as a partner. They can deliver prototypes within three weeks, and provide full integration up to packaging. (While you’re waiting for this presentation to be posted on the SOI Consortium website, you might want to refer to a similar presentation given recently by ST in Tokyo.)


In SOI: An Enabler for RF Innovation and Wireless Market Disruption, Peter Rabbeni, Director of RF Segment Marketing at GlobalFoundries, focused on the value of SOI in RF, and explained why it presents an important opportunity for innovation at the system level.


GF is the foundry partner for Peregrine (now part of Murata), and he showed how the GlobalONE PA integration is an excellent example of innovation opportunities.


With an example of tunable filters, he also posited that the combination of FD-SOI and RF-SOI is a way to create disruption in wireless markets.




Incize is a spin-off of UCL in Belgium, which is a powerhouse in RF characterization. In fact, Soitec’s trap-rich SOI wafers, which are now being commercialized under the eSI moniker and launching a veritable RF revolution, were developed in partnership with UCL (you can read about that here). In his presentation entitled RF SOI: from Material to ICs – an Innovative Characterization Approach, Incize CEO Mostafa Emam explained non-destructive characterization for RF. Incize is currently working with eight customers, including wafer manufacturers. He highlighted the value of RF-SOI, and showed the characterization of Trap Rich vs. previous generations of high-resistivity (HR) SOI.


Barend Van Liempd, PhD Researcher at IMEC (Perceptive Systems dept.) / Leuven & Vrije Universiteit Brussel (VUB) (ETRO dept.,) gave a talk entitled Towards a Highly-Integrated Front-End Module in RF-SOI Using Electrical-Balance Duplexers. (He also presented this in a paper at ISSCC a few days prior.) He covered a highly integrated FEM program at Imec based on IBM technology and Electrical-Balance Duplexers.

More Workshops Coming

If you’d like to learn more about RF-SOI and/or FD-SOI, members of the SOI Consortium have been organizing these workshops around the world for the last six years (all the presentations from all the workshops are available here) and each one builds the momentum. But the workshops over the last six months (in Shanghai, Tokyo and now San Francisco) have taken that momentum to new levels. So keep an eye out for upcoming events throughout the coming year, where more and more users will be sharing their FD-SOI and RF-SOI design experiences.


How SOI wafers for RF predict LTE-A/5G device performance

Soitec has developed an innovative metrology and metric for ensuring that devices built on our latest SOI wafers for RF will meet the draconian demands of LTE-Advanced (LTE-A) and 5G network standards.

For smartphones and tablets to handle LTE-A and 5G, they need RF devices with much higher linearity than those running over the current 2G, 3G, 4G and LTE network generations. These next generation network standards require mobile devices to support more bands, higher frequency bands, and emission and reception on adjacent bands with downlink and uplink carrier aggregation. (Carrier aggregation refers to the simultaneous reception of multiple frequency bands to improve data throughput.)

Soitec recently announced eSI90, our newest generation of trap-rich, high-resistivity SOI wafers for LTE-A and 5G. eSI90 extends our existing line of eSITM (enhanced Signal Integrity) wafers, the first generation of which are currently being used by leading manufactures to produce more than a billion RF devices every quarter.

This article gives an overview of how Soitec developed a new metric using innovative metrology on its wafers in order to predict the RF performance of final devices manufactured on eSI substrates. (Readers wanting greater detail can also consult our complete white paper on the subject, which is freely available to download here.)

Wafer specs evolve to meet new standards

To address the different communication standards and functions used in front-end modules, Soitec, the leader in SOI technology, has developed two flavors of RF-SOI products – high-resistivity (HR)-SOI and Enhanced Signal Integrity TM (eSI) SOI – both of which are compatible with standard CMOS processes. While standard HR-SOI wafers (which we introduced over a decade ago) are capable of meeting 2G or 3G requirements, eSI SOI can achieve much higher linearity and isolation specifications, allowing designers to address some of the most stringent LTE requirements. (We detailed how advanced RF design challenges are solved by eSI wafers in a 2013 ASN article – you can still read it here.) This paves the way for integrating more functions on a device with better RF performance at competitive cost.


Soitec’s enhanced Signal Integrity™ (eSI) wafers integrate a trap-rich layer under the insulating BoX in a high-resistivity (HR) SOI wafer (Image courtesy of Soitec)


eSI wafers leverage the addition of a “trap-rich” layer to high-resistivity (HR) SOI wafers, an approach that was developed by UCL and Soitec (that project was covered in an ASN piece explaining the technical details at the time – you can read it here).


Change at all levels

The IIP3 linearity requirements for 3G are +65dBm. For LTE, they increased to +72dBm, and for LTE-A, they are over +90dBm. For RF designers, this has added substantially to the complexity of RF Front-End Modules (FEMs), and entails multiple changes for each of the main functions: switches, power amplifiers, power management and antenna tuners.


Example of Front-End Module Block Diagram for 3G


Example of Front-End Module Block Diagram for LTE


These latest front-end modules need to support more bands, higher frequency bands from 700 MHz to 3.5 GHz, larger bands from 20 MHz to100 MHz and carrier aggregation downlink and uplink, sometimes on adjacent bands. This means:

  • A proliferation of switches on top of the antenna switch including diversity, power-mode and antenna-swapping switches
  • Advanced, tunable power-amplifier architectures to achieve compact and cost-effective multi-mode, multi-band transmission in a single broadband power amplifier
  • Advanced power management: with an envelope-tracking system approach, the efficiency of broadband power amplifiers will be close to or as good as that of single-band power amplifiers
  • Advanced wide-band antenna: with an antenna-tuner system performing either impedance matching and/or aperture tuning, an antenna can efficiently cover bands with frequencies from 700 MHz to 3.5 GHz with optimum efficiency and a smaller footprint

To meet the required performance, many changes are happening at all levels, from systems, architectures, design, manufacturing processes, devices – right down to where it all starts: the substrates. The substrates on which RF devices are manufactured have a significant impact on the level of performance that the final chips will be capable of achieving.

Characterizing eSI wafers

To quantify the performance designers can expect from an eSI SOI substrate, Soitec has now developed an innovative characterization method based on spreading resistance profiling (SRP), which can predict the 2nd harmonic distortion (HD2) performance of a coplanar waveguide. This solution is used today throughout the Soitec eSI product line to ensure the substrates will enable the expected RF performance in the finished devices.

We predict the RF harmonic distortion performance of the substrate immediately after the eSI SOI substrates are fabricated and before any devices are manufactured on them. This prediction is provided through a metric we call the harmonic quality factor (HQF).

HQF correlates with the second harmonic distortion generated from a 900-MHz signal applied to a coplanar waveguide (CPW) deposited on the substrate.

The CPWs are implemented on sample test wafers by depositing aluminum metal lines on the buried oxide of eSI SOI wafers after the Smart Cut process has been completed and the top silicium removed.

Then a 900-MHZ fundamental tone is applied on one end of the CPW line and the HD2 signal is measured at the other, providing a value of the HD2 generated by the substrate. Then, using the same wafers, a Spreading Resistance Profiling (SRP) technique measures the resistivity of the material at different depths under the buried oxide.

Next, we use a proprietary algorithm to compute the series of measures. The algorithm, tuned to match various HD2 values, takes into account the resistivity of the substrates weighted by the depth of the measure, and gives us the HQF.

Soitec has implemented this metrology on its production eSI SOI wafers and is sampling products to carry the HQF measurement.

To address different market requirements, we set our HQFmax specification at -80 dBm for eSI-G1 (first-generation eSI product) and at -90 dBm for our eSI90 (second-generation eSI product).


HQF specifications for Soitec’s 1st and 2nd generation eSI products (eSI-G1i and eSI90, respectively) correlated with linearity requirements.


HQF metrology, conducted at the substrate level, provides a reliable measure of the finished devices’ RF performance. It is now being used by Soitec to report the expected RF linearity performance of ICs manufactured with RF-SOI substrates.

As a solution addressing the current and next generation of RF standards, eSI SOI wafers are enabling this market by meeting some of the most difficult LTE and LTE Advanced linearity requirements. Soitec is able to provide its customers with the eSI SOI substrates that meet their desired level of RF performance.


LTE-A/5G: Bring it on. Next-gen Soitec eSI90 wafers predict & improve RF performance.

The folks at SOI wafer maker Soitec have announced an amazing update to their RF wafer line-up, with what they’re calling their eSI90 substrate (read the press release here). As you might expect, it improves on their terrifically successful line of substrates for the RF chips in smartphones and other mobile devices. And now with this latest substrate, they’ve developed metrology that allows designers to predict the linearity of finished RF devices, ensuring they meet the demands for next-gen networks.

SOI wafers for RF are mainly 200mm (8”) in diameter. Soitec CEO Paul Boudre says they’ll continue to run at full capacity in 2015-2016. Additional wafers will also be available through Soitec’s partnership with Simgui in China.

(Courtesy: Soitec. (C) photo Christian Morel / www.morel-photos.com)

(Courtesy: Soitec. (C) photo Christian Morel / www.morel-photos.com)

How successful is this line? “Today, we estimate that more than one billion RF devices are produced each quarter using our eSI wafers,” says Dr. Bernard Aspar, senior vice president and general manager of Soitec’s Communication & Power Business Unit.  That’s for 2G, 3G and now 4G and LTE.

But with the advent of LTE-Advanced (aka LTE-A), 5G and Wi-Fi 802.11.ac (aka Gigabit Wi-Fi), RF designers need a whole lot more linearity in finished devices. That’s where eSI90 comes in.

Why? We’re looking at a 10x increase in smartphone data traffic (much of it due to high-def video) between 2013 and 2018, with average connection speeds jumping from 4Mbps to 7 Mbps.


SOI wafers. (Courtesy: Soitec)

But to achieve the throughput needed, designers are faced with draconian linearity requirements and far more complex front-end modules (FEM). The wafer substrate they start on has a major impact on the performance level of the final devices.

Seeing this coming, a few years ago Soitec teamed up with experts at the Université catholique de Louvain (UCL). Leveraging Soitec’s Smart Cut™technology, they developed and industrialized the addition of a “trap-rich” layer in high-resistivity (HR) SOI wafers (if you missed it, they wrote an excellent ASN piece explaining the technical details at the time – you can read it here).

The first generation of these trap-rich HR SOI wafers, which Soitec called eSI (for enhanced Signal Integrity), was a tremendous success from the get-go. Designers loved that the wafers enabled relaxed design rules, reduced process steps and gave them highly competitive performance and die cost, including a smaller area per function (well explained here).

So here’s what’s new about the new eSI90 wafers: they exhibit higher effective resistivity than first-generation eSI wafers, enabling a 10-decibel (dB) improvement in linearity performance in RF front-end modules to address the stringent new requirements of LTE-A smart phones.

Those eSI90 SOI wafers are designed to improve the RF performance of mobile communication components such as high-linearity switches and antenna tuners that are integrated in high-end smart phones for LTE-A networks using carrier aggregation. This enables multiple LTE carriers to be used together, providing higher data rates to enhance user experience.

To ensure that the new wafers would deliver on their promise, the Soitec team developed a new metrology metric, the Harmonic Quality Factor (HQF), to predict the expected RF linearity of finished ICs. We’ll have a more in-depth explanation of how this works coming up in ASN from the Soitec team. But for now, designers will appreciate that HQF correlates with the second harmonic distortion value of a coplanar waveguide deposited on the substrate. The new eSI90 wafers’ HQF maximum value is set to -90 decibel- milliwatts (dBm) compared to -80 dBm for first-generation eSI substrates. The lower limit on eSI90 wafers enables chipmakers to take advantage of design and process improvements to increase the RF performance of their chip designs and to meet MIMO (Multi-Input Multi-Output) and Carrier Aggregation LTE-A requirements, providing faster data connections.

The new eSI90 substrates are already under evaluation at leading chipmakers and foundries. Production-ready samples are now available from Soitec.

When it comes to next-gen mobile design, innovation really does start at the substrate level.


Successful RF-SOI 2014 International Symposium Held in Shanghai

A very successful international workshop on RF-SOI was held in Shanghai earlier this fall.  Jointly organized by industry leaders, it brought together world-class players in RF to discuss the opportunities and challenges in rapid development of RF applications.Sponsors included the SOI Industry Consortium, the Chinese Academy of Sciences (CAS) / Shanghai Institute of Microsystem and Information Technology (SIMIT), Shanghai Industrial μTechnology Research Institute Co.,Ltd. (SITRI) and VeriSilicon.

The first talk, given by Dr. Xi Wang, Academician of CAS and Director General of SIMIT, covered China’s huge market prospects for RF applications. RF-SOI, he noted, is an area in which Shanghai Simgui Technology Co.,Ltd. ,  a spin-off company from SIMIT,  and French SOI wafer manufacturer Soitec are working closely to explore the market opportunities now. He also presented some of the latest research findings and the industry dynamics in this field.

Xi Wang, Academician and Director General of the Shanghai Institute of Microsystem and Information Technology (SIMIT) /Chinese Academy of Sciences (CAS) giving the first talk at the 2014 International RF-SOI Workshop.

Xi Wang, Academician and Director General of the Shanghai Institute of Microsystem and Information Technology (SIMIT) /Chinese Academy of Sciences (CAS) giving the first talk at the 2014 International RF-SOI Workshop.


Next, Handel Jones, CEO of IBS, gave a detailed analysis of the markets for smart phones and tablet PCs and other mobile consumer applications. These are strong drivers of the huge market opportunity and demand for chips based on RF-SOI technology. (Click here to view his presentation.)


(Courtesy: IBS)

(Courtesy: IBS)

This workshop also featured presentations by ST, GlobalFoundries and SMIC, as well as several important RF-SOI platform providers.

Mark Ireland, Vice President of Strategy and Business Development at the IBM Microelectronics Division, noted that that IBM first began offering RF-SOI manufacturing in 2006.  He explained the key role RF-SOI plays in redefining chips for mobile applications, where integration and performance are key. (Click here to view his presentation.)

Laura Formenti, Infrastructure and RF-SOI Business Unit Director at STMicroelectronics, gave a detailed analysis of RF-SOI. She covered the advantages of RF front-end integration and introduced ST’s H9SOI_FEM technology platform. (Click here to view her presentation.)

Paul Colestock, Sr. Director of Segment Marketing at GlobalFoundries shared specifics and the latest developments in the 130nm RF-SOI technology platform, UltraCMOS 10.


The room was full at the Shanghai RF-SOI Workshop 2014

The room was full at the Shanghai RF-SOI Workshop 2014


Herb Huang, Sr. Director Development, Technology R&D at SMIC, China’s largest foundry, addressed SOI in RF switches. He shared details on SOI NFETs for enhanced performance, and on CMOS MEMS RF filters. SOI CMOS will facilitate integration of switches (SW), power amplifiers (PA), envelope tracking (ET) and antenna tuning (AT) in SoCs. The foundry provides not only device-level processes but also support for high-performance system-in-package (SiP) solutions at the wafer level.

Professor Jean-Pierre Raskin of the Catholic University of Leuven (Belgium) and Bernard Aspar, General Manager of Soitec’s Communication & Power Business Unit presented detailed technical analyses of SOI substrates.  They covered the influence of substrates on RF signal integrity and the key role they play in improving RF performance thanks to the enhanced Signal Integrity (eSI™) High Resistivity SOI substrate.  (Click here to view the UCL presentation, and here to view the Soitec presentation.)

James Young, VP of Engineering, FES Si Platform Engineering at Skyworks focused on RF and wireless semiconductor design. In particular he addressed mobile phone design, including PA, ET and APT (Average Power Tracking). He gave performance comparisons and analysis for SOI/CMOS vs. GaAs devices.  (Click here to view the presentation.)

Dr. Yumin Lu, VP of the Shanghai Industrial μTechnology Research Institute Co.,Ltd. elaborated on how 4G wireless communications brings new challenges for RF front-end modules and components. RF-SOI has become a mainstream technology for antenna/switches. There is also significant potential for RF-SOI to make further inroads in applications such as tunable components (including antennas, PAs, filters/duplexers, etc.). (Click here to view the presentation.)


Roundtable Discussion at the 2014 International RF-SOI Workshop in Shanghai

The final panel discussion session on the “China RF market” started a lively debate. Topics included the specificities and drivers of the China RF market, Chinese foundry capacity, the RF-SOI supply chain, RF front-end module (FEM) system packaging and system integration trends, and LTE and WiFi common platforms on RF-SOI substrates.  Audience members had questions about device design. The need for the industry to establish a broader ecosystem was a common theme.

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Editor’s note: This article was first posted in Chinese at Shanghai Institute of Micro-Technology Industry Views. You can see the original hereMany thanks to Xi Wang, Academician and Director General of the Shanghai Institute of Microsystem and Information Technology (SIMIT) /Chinese Academy of Sciences (CAS) for his permission to translate/adapt and reprint it here in ASN.