Interested in energy-efficient SOCs? At the IP-SOC Conference last fall, STMicroelectronics’ Giorgio Cesana presented examples of the technological competitiveness of FD-SOI IP for memories, cores, ultra-low voltage and analog.
Here’s a brief recap. The complete presentation, entitled “FD-SOI Technology for Energy-Efficient SoCs: IP Development Examples” is available on the Design & Reuse website (click here to view it).
Memory is the proverbial canary in the coal mine for chip designers. To run reliably, pairs of transistors can’t be mismatched – and this becomes more critical with the lowering of the supply voltage (Vdd), nowhere more so than in memory. FD-SOI decreases mismatching by 40% compared to low-power (LP) bulk, and decreases leakage by a factor of 8. Soft error rates (SER) are 100x better in FD-SOI than in bulk. And of course, being able to run at lower voltages can make a significant contribution to battery savings in portable devices.
In the example of a dual ARM A9 subsystem architecture, ST’s IP is used to generate programmable body voltages, enabling a CPU to run at 300 MHz with a 0.5V supply voltage. Increasing the supply voltages increases the performance: up to 2.3 GHz at 1V, and on to 3 GHz at 1.34V. And with forward body biasing (FBB), which is only possible in FD-SOI, you get 1GHz at 0.6V when you need it.
Dynamic process scaling, thanks to extended body biasing, allows dynamic switching between high-speed and static-power optimizations. In a multi-core context the effects are dramatic.
Ultra-Low Voltage Apps
For things like medical devices and Internet of Things (IoT) apps, the ultra-low voltage design enabled by FD-SOI should be a key differentiator.
The presentation shows that ST is particularly pleased to emphasize what analog designers can do with FD-SOI. For example, in a switch the resistance ratio between on and off (Ron/Roff) is 10x better in FD-SOI than in bulk or FinFETs. Power signal gains are improved by 6x without using pocket implants, and matching is better in short-channel devices because there is no channel doping.
Here at ASN, we’ll have lots more good news and useful information coming your way from the FD-SOI design community in the weeks and months to come. So if you haven’t signed up for a free subscription* yet, now’s the time! Just click here and fill in the form.
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Two SOI pioneers have been elevated to the status of Fellow by the IEEE for their extraordinary accomplishents:
The new IEEE S3S conference promised rich content, as it merged both The IEEE International SOI Conference and the IEEE Subthreshold Microelectronics Conference, completed by an additional track on 3D Integration.
The result was an excellent conference, with outstanding presentations from key players in each of the three topics covered. This quality was reflected in the increased attendance: almost 50% more than at the SOI conference last year.
The new triptych at the heart of the conference was well illustrated by the plenary session, which combined a presentation on ST’s FD-SOI technology by Laurent LePailleur (STMicroelectronics), one on Low Power Design, by Bob Bordersen (UC Berkeley), and one on monolithic integration by Zvi Or-Bach (MonolithIC 3D™).
Professor Bordersen’s presentation dealt with power efficiency, explaining how developing dedicated units with a high level of parallelism and a low frequency can boost the number of operations performed for 1nJ of expanded power. He illustrated his point by showing how an 802.11a Dedicated Design for Computational Photography can reach 50,000 OP/nJ while an advanced quadcore microprocessor will not even reach 1 OP/nJ. Such is the price of flexibility….but the speaker claims this can be overcome by using reconfigurable interconnects.
The “Best SOI Paper” award went to a GlobalFoundries/IBM paper entitled “FinWidth Scaling for Improved Short Channel Control and Performance in Aggressively Scaled Channel Length SOI FinFETs.” The presenter, Abhijeet Paul (GF) explained how narrower Fins can be used to improve short channel effects while actually giving more effective current without degrading the on-resistance. (See the DIBL and SS improvement on the chart.)
The”Best SOI Student Paper” award went to H. Niebojewski for a detailed theoretical investigation of the technical requirements enabling introduction of self-aligned contacts at the 10nm node without additional circuit delay. This work by ST, CEA-Leti and IEMN was presented during the extensive session on planar FD-SOI that started with Laurent Grenouillet’s (CEA-Leti) invited talk. Laurent first updated us on 14nm FD-SOI performance: Impressive static performance has been reported at 0.9V as well as ROs running at 11.5ps/stage at the very low IOFF=5nA/µm (0.9V & FO3). Then he presented potential boosters to reach the 10nm node targets (+20% speed or -25% power @ same speed). Those boosters include BOX thinning, possibly combined with dual STI integration, to improve electrostatics and take full advantage of back-biasing as well as strain introduction in the N channel (in-plane stressors or sSOI) combined with P-channel germanidation.
sSOI (strained SOI) was also the topic of Ali Khakifirooz’ (IBM) late news paper, who showed how this material enables more than 20% drive current enhancement in FinFETs scaled at a gate pitch of 64nm (at this pitch, conventional stressors usually become mostly inefficient).
An impressive hot topics session was dedicated to RF CMOS.
J. Young (Skyworks) explained the power management challenges as data rates increase (5x/3 years). Peak power to average power ratio has moved from 2:1 to 7:1 while going from 3G to LTE. Advanced power management techniques such as Envelope Tracking can be used to boost your system’s efficiency from 31% to 41% when transferring data (compared to Average Power Tracking techniques), thus saving battery life.
Paul Hurwitz (TowerJazz) showed how SOI has become the dominant RF switch technology, and is still on the rise, with predictions of close to 70% of market share in 2014.
The conference also had a strong educational track this year, with 2 short courses (SOI and 3DI) and 2 fundamentals classes (SOI and Sub-Vt).
The SOI short course was actually not SOI-restricted, since it was addressing the challenges of designing for a new device technology. P. Flatresse (ST) and T. Bednar (IBM) covered the SOI technology parts (FD-SOI and SOI FinFETs for ASICs respectively), while D. Somasekhar (Intel) gave concrete examples of how the change of N/P performance balance, the improvement of gate control or the introduction of Mandrels has affected design. Other aspects were also covered: Design for Manufacturing (PDF), IP librairies (ARM) and design tools (Cadence) for the 14nm node, to make this short course very comprehensive.
The rump session hosted a friendly discussion about expectations for the 7nm node. It was argued that future scaling could come from 3DI, either through the use of monolithic 3D integration or stacking and TSVs because traditional scaling is facing too many challenges. Of course, 3DI may not yet be economically viable for most applications, and since it is compatible with traditional scaling, we might well see both developed in parallel.
3D integration was also the topic of another joint hot topics session covering various fields of investigation, like co-integration of InGaAs and Ge devices (AIST), or 3D cache architectures (CEA-Leti & List). A nice example was given by P. Batra (IBM) of two stacked eDRAM cache cores, where the 16Mb cache on one layer is controlled by the BIST on the other layer and vice-versa with the same efficiency as in the 2D operation.
The first edition of this new conference was very successful, with a good attendance, two sessions running in parallel, extensive educational tracks, a large poster session and a lot of very high quality content. The two hot topics sessions generated a lot of enthusiasm in the audience.
Similar sessions will be repeated at the conference’s next edition, in the San Francisco area. It promises to offer outstanding content once more, and we already urge you to plan to submit papers and attend it.
Last May, we already let you know about the IEEE S3S conference, founded upon the co-location of The IEEE International SOI Conference and the IEEE Subthreshold Microelectronics Conference, completed by an additional track on 3D Integration.
Today, we would like let you know that the advance program is available, and to attract your attention on the incredibly rich content proposed within and around this conference.
The conference revolves around an appropriate mix of high level contributed talks from leading industries and research groups, and invited talks from world-renowned experts.
The complete list of posters and presentations can be seen in the technical program.
This year some additional features have been added, including a joint session about RF CMOS as well as one about 3D integration. Check the list of participants on those links, and you will see that major players in the field are joining us!
Our usual rump session will let us debate what the 7 nm node and beyond will look like, based on the vision presented by our high profile panelists.
There will be 2 short courses this year, and 2 fundamentals classes. Those educational tracks are available to you even if you do not register for the full conference.
On Monday October 7th, you can attend the short course on “14nm Node Design and Methodology for Migration to a New Transistor Technology“, that covers specificities of 14nm design stemming from the migration of classical bulk to bulk to FinFET/FDSOI technologies..
Alternatively, on the same day you can attend the “3D IC Technology” short course, introducing the fundamentals of 3D integrated circuit technology, system design for 3D, and stress effects due to the Through Silicon Via (TSV).
On the afternoon of Wednesday October 9th, you can opt to follow the Sub Vt Fundamentals Class on “Robust subthreshold ultra-low-voltage design of digital and analog/RF circuits” or the SOI Fundamentals Class “Beyond SOI CMOS: Devices, Circuits, and Materials “.
You could also prefer to take the opportunity to visit the Monterey area.
The conference has always encouraged friendly interactions between the participants, and because it covers the complete chain, from materials to circuits, you are sure to meet someone from a field of interest. The usual social events, welcome reception, banquet and cookout dinner, will provide you with more openings for networking, contemplating new project opportunities or getting into technical discussions that could shed new light on your research.
To take full advantage of this outstanding event, register now!
Please visit our Hotel Registration Information page to benefit from our special discounted room rates at the conference venue, The Hyatt Regency Monterey Hotel and Spa.
The latest conference updates are available on the S3S website (http://S3Sconference.org).
PCMag’s Michael Miller called IBM’s 22nm SOI Power8 “the most fascinating” of the high-end processors. Reporting on this year’s Hot Chips conference, presented there. He noted that the chip “will have 12 cores, each capable of running up to eight threads, with 512KB of SRAM Level 2 cache per core (6MB total L2) and 96MB of shared embedded DRAM as a Level 3 cache.” He cites the eDRAM, which ASN readers first learned about in an ’06 article by Subi Iyer, the IBM father of eDRAM – when he explained, “The complexity adder is about half in SOI compared to bulk for deep trench based eDRAMs.”
Miller also says, “Compared with the previous generation Power 7+, which was manufactured on a 32nm SOI process, Power8 should have more than twice the memory bandwidth at 230GBps. IBM says each core should have 1.6 times the performance of Power7 on single-threaded applications and twice the SMT (symmetric multi-threaded) performance.”
With the upcoming Hybrid Memory Cube (HMC) from Micron et al, SOI becomes an integral part of 2.5D and 3D stacks, notes SemiMD’s Ed Sperling. “The logic base layer—in this case made by IBM—uses an SOI substrate,” he explains, “…even if some of the other pieces use different materials.” He goes on to say that while the next-gen HMC enters production at the end of next year, in the meantime the existing HMC architecture can be attached to FPGAs, either in a vertical stack or in a 2.5D configuration. “Having an additional layer of insulation is a bonus in that architectural arrangement, as well, to buffer against a variety of physical effects ranging from noise to heat.”
Targeting low-power SRAM for FD-SOI and FinFETs, UK physical IP start-up sureCore has received a £250K grant (about 292K Euros or $380.5K) from the Technology Strategy Board SMART. Working with the major foundries developing FD-SOI and FinFET technologies, the grant will be used in the development of a demonstrator chip to showcase sureCore’s patented array control and sensing scheme, which significantly lowers active power consumption. Through a combination of detailed analysis and using advanced statistical models, sureCore has designed an SRAM memory consuming less than half the power of existing solutions. SureCore is working closely with Gold Standard Simulations (GSS) Ltd. (GSS Founder/CEO Asen Asenov is a sureCore director).