Renesas Electronics will be coming out with chips built on 65nm FD-SOI technology by spring of 2016, reports EETimes Japan (see article in Japanese here, or a version translated by Google here). Although the story dates from February 2015, it has barely been covered in the English-speaking press. (FD-SOI expert Ali Khakifirooz talked about it briefly in a SemiWiki piece last month entitled FDSOI As a Multi-Node Platform, which you can read here). The chips can operate down to 0.4V, and consume 1/10th of the power of previous generations.
If you’ve been reading ASN right along, you might already know about it, from our piece last year on the Semicon Europa (’14) Low Power Conference (read it here). At the time, Renesas talked about a demo they’d done of a 32 bit CPU on 65nm SOTB (aka Silicon on Thin Box, which is a planar FD-SOI technology) with back bias that operates eternally (!!) with ambient indoor light.
Renesas has roots with Hitachi, which was an early SOTB/FD-SOI innovator. In fact, here at ASN we had a Hitachi/Renesas piece in ASN on SOTB back in 2006 (read it here), highlighting work they’d presented at IEDM in 2004. Then in 2010, Dr. Sugii, who’s a very highly respected researcher, wrote in ASN advocating SOTB for older nodes (read that here). So this has been in the works for a while. Does this not put these companies in an incredibly strong position for IoT?
ST further accelerates its FD-SOI ROs* by 2ps/stage, and reduces SRAM’s VMIN by an extra 70mV. IBM shows an apple-to-apple comparison of 10nm FinFETs on Bulk and SOI. AIST improves the energy efficiency of its FPGA by more than 10X and Nikon shows 2 wafers can be bonded with an overlay accuracy better than 250nm.
We learned all this and much more during the very successful 2014 IEEE S3S Conference.
The conference’s 40th edition (first created as the IEEE SOS technology workshop in 1975) was held in San Francisco Oct. 6-9. Dedicated to central technologies for tomorrow’s mainstream applications, the event boasted nearly 80 papers presented over 3 days covering conception, design, simulation, process and characterization of devices and circuits.
Many of the talks we heard made it very clear that the Internet-of-Things will be the next big market growth segment. It will be enabled by extremely energy-efficient and low-cost technologies in the field of RF-communications, sensors and both embedded and cloud computing. The program of the conference was very well designed to tackle these topics, starting with the short courses on Energy Efficiency and Monolithic 3D, an RF fundamentals & applications class, a MEMS hot topic session and a strong focus on ultra-low power throughout the SubVt sessions.
The interest of the participants could be seen through an increase in Short Course and Fundamentals Class participation (+20%) compared to last year.
The companies working in the field of RF communications and mobile chips were well represented, including attendees and presenters coming from Broadcom, MediaTek, Murata, Newlans, Qualcomm, RFMD, Skyworks and TowerJazz.
The SubVT portion of the conference featured an extremely strong suite of papers on advancements in subthreshold circuit design including ultra-low-voltage microprocessors, FPGAs, and analog circuits. Additionally, there were sessions on technologies which enable very low voltage computation, such as radiation testing during subthreshold operation, and efficient energy-harvesting devices to allow indefinite operation of IoT systems. A number of talks explored the future of ultra low voltage computing, presenting results from emerging technologies such as Spin Torque Transfer devices and TFETs.
The 3D integration track keeps growing in the conference and is strongly focused on monolithic 3D. A dedicated full day short course was offered again this year, as well as two joint sessions featuring several papers on process integration, design, precision alignment bonders and more. Progress is being made and a lot of interest in this technology is being generated (See the EE Times article).
Planar Fully-Depleted SOI technologies were well represented again this year, in both SOI and Sub-Vt parallel sessions. A full session was also dedicated to FinFETs.
STMicroelectronics and CEA-Leti gave us a wealth of information on:
How to improve your circuit’s efficiency by co-optimizing Vdd, poly-bias and back-gate voltage simultaneously during the circuit design. Picking the correct optimization vector enables you to gain more than 2X in speed or up to 5X in power compared to the non-optimized circuit. (P. Flatresse, “Design Strategy for Energy Efficient SOCs in UTBB FD-SOI Technology” in the “Energy Efficiency” short course). In the same presentation we saw how going to a single-well configuration can help further reduce SRAM’s VMin by 70mV (see graph to the right).
The latest updates on 14nm technology, including an additional 2ps/stage RO delay reduction since the 2014 VLSI results shown last June. This means ROs running faster than 8ps/stage at 10nA/stage of static leakage. The key elements for the 10nm node (sSOI, thinner BOX, replacement gate, next gen. ID-RSD) where also discussed. (M. Haond, “14nm UTBB FD-SOI Technology”).
In the past year we witnessed the foundry announcements for FD-SOI technology offering. Global Foundries very clearly re-stated their interest in the FD-SOI technology, claiming that 28FD-SOI is a good technology for cost sensitive mobile applications, with the cost of 28LP and the performance of 28HPP. However, GF favors a flavor of FD-SOI technology they call Advanced ET-SOI, with similar performance to 20LPM at a reduced cost.
The IEEE S3S Conference Best Paper Award went to Hanpei Koike and co-authors from the National Institute of AIST, for their paper entitled “More than An Order of Magnitude Energy Improvement of FPGA by Combining 0.4V Operation and Multi-Vt Optimization of 20k Body Bias Domains,” presented in the SubVT part of the conference. In this work, an FPGA was fabricated in the AIST SOTB (Si On Thin BOX — which is another name for FD-SOI) process, and demonstrated successful operation down to voltages at and below the minimum energy point of the circuit. A 13x reduction in Power-Delay-Product over conventional 1.2V operation was achieved through a combination of low voltage operation and flexible body-biasing, enabled by the very thin BOX.
On the FinFET side, T.B. Hook (IBM) presented a direct comparison of “SOI FinFET versus Bulk FinFET for 10nm and below”, based on silicon data. This is a very unique work in the sense that both technologies are being developed and optimized by the same teams, in the same fab, with the same ground rules, which enables a real apple-to-apple comparison. SOI comes out a better technology in terms of Fin height control (better performance and ION variability), VT mismatch (lower VMin), output conductance (better analog and low voltage perf.) and reliability. Though external stressors are expected to be more efficient in Bulk FinFETs, mobility measurements are only 10% lower for SOI PFETs and are actually 40% higher for SOI NFETs, because of the absence of doping. The devices’ thermal resistance is higher on SOI, though bulk FinFETs are not as immune to self-heating as planar bulk. Both technologies are still competitive down to the 10nm node, but looking forward, bulk’s advantages will be rendered moot by the introduction of high mobility materials and dimensions shrinking, while SOI advantages will keep getting larger.
Next year, the S3S Conference will be held October 5-8, at the DoubleTree by Hilton Sonoma Wine Country Hotel, Rohnert Park, California.
The organizing committee is looking forward to seeing you there!
Steven A. Vitale is an Assistant Group Leader in the Quantum Information and Integrated Nanosystems Group at MIT Lincoln Laboratory. He received his B.S. in Chemical Engineering from Johns Hopkins University and Ph.D. in Chemical Engineering from MIT. Steven’s current research focuses on developing a fully-depleted silicon-on-insulator (FDSOI) ultra-low-power microelectronics technology for energy-starved systems such as space-based systems and implantable biomedical devices. Prior to joining MIT-LL, Steven was a member of the Silicon Technology Development group at Texas Instruments where he developed advanced gate etch processes. He has published 26 refereed journal articles and holds 5 patents related to semiconductor processing. From 2011 to 2012 Steven was the General Chair of the IEEE Subthreshold Microelectronics Conference, and is on the Executive Committees of the AVS Plasma Science and Technology Division, the AVS Electronic Materials and Processing Division, and the IEEE S3S Conference.
Frederic Allibert received his MS degree from the National Institute for Applied Sciences (INSA, Lyon, France) in 1997 and his PhD from Grenoble Polytechnic’s Institute (INPG) in 2003, focusing on the electrical characterization of Unibond wafers and the study of advanced device architectures such as planar double-gate and 4-gate transistors. He was a visiting scientist at KAIST (Taejon, Korea) in 1998 and joined Soitec in 1999. As an R&D scientist, he implemented SOI-specific electrical measurement techniques (for thin films, multi-layers, high resistivity) and supported the development of products and technologies targeting various applications, including FD-SOI, RF, imagers, and high-mobility materials. As Soitec’s assignee at the Albany Nanotech Center since 2011, his focus is on substrate technologies for advanced nodes. He has authored or co-authored over 50 papers and holds over 10 patents.
*RO = ring oscillator
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).
There’s no need to wait – Hitachi’s SOTB solution also benefits today’s mainstream low-power nodes.
Hitachi’s Hybrid Silicon-On-Thin-Box (SOTB)-Bulk technology offers many benefits for low-power system-on-chips (SOCs) at 45nm – and even at 65nm. There is no reason to wait for 22nm to start taking advantage of them.
The four most significant reasons to change to this solution now rather than later are that hybrid SOTB:
1. cuts power and leakage in half
2. gets threshold voltage (Vt) and variability under control
3. is fully compatible with current bulk design is easy to manufacture.
4. is easy to manufacture. Read More
Hitachi demonstrates why it has the smallest Vth variability, and identifies the remaining components of random doping fluctuation.
In a “Comprehensive Study on Vth Variability in Silicon on Thin BOX (SOTB) CMOS with Small Random-Dopant Fluctuation: Finding a Way to Further Reduce Variation,” (N. Sugii et. al., IEDM 2008) Hitachi scientists at the Central Research Laboratory demonstrated that the planar FDSOI devices fabricated on SOTB have the smallest Vth variability among planar CMOS due to low-dose channel and back bias control. Read More