Category Archives: Semiconductors

The pattern of arrangement of atoms in a crystal, called the crystal lattice, can have a huge effect on the properties of solid materials. Controlling and harnessing these properties is a challenge that promises rewards in applications such as novel sensors and new solid-state devices. An international research collaboration, including researchers from Osaka University, has reported the induction of an interesting type of magnetic order, called helimagnetism, in a cobalt oxide material by expanding its lattice structure. Their findings were published in Physical Review Materials.

This is a schematic illustration of the helimagnetic-ferromagnetic transition driven by the lattice expansion/compression in the cubic perovskite Sr1-xBaxCoO3. Credit: S. Ishiwata and H. Sakai

Magnetic behavior results from the order of the magnetic moments of the many individual atoms in a material. In helimagnetism, instead of the magnetic moments being aligned–as they are in permanent magnets, producing ferromagnetism–the moments arrange themselves in a helical pattern. This behavior is generally only observed in complicated lattice structures where different types of magnetic interactions compete with each other, therefore the report of induced helimagnetism in a simple cubic cobalt oxide structure, is highly significant.

“We have shown emergent helical spin order in a cubic perovskite-type material, which we achieved simply by expanding the lattice size,” study first author Hideaki Sakai says. “We were able to control the size of the lattice expansion by using a high-pressure technique to grow a series of single crystals with particular chemical compositions. Changing the amount of different ions in our materials provided us with sufficient control to investigate the magnetic properties.”

Systematically replacing strontium ions in the structure with larger barium ions caused the lattice to continually expand until the regular ferromagnetic magnetic order present at room temperature was disrupted, resulting in helimagnetism. These experimental findings were successfully supported by calculations.

“The fact that we were able to largely reproduce our findings by first principles calculations verifies that the magnetic interactions in the materials are highly sensitive to the lattice constant,” Sakai says. “The more we can understand about the magnetic behavior of crystalline materials, the closer we move towards translating their properties into useful functions. We hope that our findings will pave the way for novel sensor applications.

The control of magnetic order simply by changing the lattice chemistry, as demonstrated by this research, provides a foundation for investigating the properties of many other crystalline materials.

Lam Research Corporation (Nasdaq: LRCX) today announced that the Board of Directors has accepted Martin Anstice’s resignation as chief executive officer and a member of the Board and has named Tim Archer president and chief executive officer (CEO) effective immediately. Mr. Archer has also been appointed to the Board of Directors of Lam Research. Prior to this appointment, Mr. Archer was the company’s president and chief operating officer (COO).

Mr. Anstice resigned as the company investigates allegations of misconduct in the workplace and conduct inconsistent with the company’s core values, including allegations about Mr. Anstice. The alleged conduct did not involve financial misconduct, nor did it relate to questions regarding the integrity of the company’s financial systems or controls. Upon learning of the allegations, the Board of Directors formed a committee of independent directors led by Lead Independent Director Abhi Talwalkar to conduct an investigation of the allegations, which is ongoing. The independent directors retained an external law firm to assist with the investigation. Mr. Anstice will be leaving the company without receiving any severance benefits.

Mr. Archer was appointed president and COO of Lam Research in January 2018, after serving as COO since June 2012 when Lam completed its acquisition of Novellus Systems, Inc. He joined Novellus in 1994 and held numerous positions throughout his tenure there, including serving as COO at the time of the acquisition by Lam Research.

“The board believes strongly in Lam’s vision and strategy. With Martin’s resignation, we are implementing our existing succession plan in which Tim was designated to succeed Martin. We are confident that Tim is the right leader to execute on the company’s strategic agenda and drive success in the coming years,” said Mr. Talwalkar. “Since joining us over six years ago with the acquisition of Novellus, Tim has been instrumental in leading Lam Research through a period of transformational growth, and we are confident our company and stakeholders will continue to prosper under Tim’s leadership.”

Mr. Archer commented, “I am honored to lead Lam Research at a time of great opportunity for our company. Lam has industry-leading technologies and is well-positioned to capitalize on the multiple demand drivers for the semiconductor industry. We are committed to our long-term strategy of value creation for our customers, employees, business partners, and stockholders.”

Mr. Talwalkar added, “Lam Research takes all allegations of misconduct seriously. An integral part of the culture of Lam Research is our commitment to provide a safe and positive work environment where each of our employees has the opportunity to thrive. The company has policies in place to support and enforce this commitment.”

Lam Research also reaffirms its financial guidance for the December 2018 quarter, as communicated in the press release dated October 16, 2018. An update to our financial performance and business outlook will be provided at our customary quarterly earnings call on January 23, 2019.

SEMI announced today that the Industry Strategy Symposium (ISS) 2019 will take place January 6-9 at Half Moon Bay’s Ritz-Carlton Hotel with the theme “Golden Age of the Semiconductor: Enabling the Next Industrial Revolution.” ISS is the year’s first executive check-in, bringing together leading analysts, researchers, economists, and technologists for insights on the forces impacting the semiconductor industry. The annual symposium offers executives a unique platform for identifying growth opportunities and gaining industry intelligence to help them ensure that their business plans and forecasts are based on up-to-the-minute market conditions. Registration for ISS 2019 is now open.

Major developments are transforming the extended supply chain — artificial intelligence (AI), intelligent vehicles, augmented and virtual reality, and seemingly limitless connectivity within the cloud. Collaboration across an expanding ecosystem and advanced technical innovations are giving rise to advanced electronics that continue to raise performance and power-consumption requirements and drive heterogenous integration.

“It can be hard to lead to where you’ve not been, particularly at this most dynamic time in business,” said David Anderson, president of SEMI Americas. “Executives from across the supply chain historically have asked for this timely ISS program in order to gauge what the year ahead looks like. To help management get the very latest picture, and to compare notes to most confidently tune their operations and sales, ISS is a tremendous level set for the new year.”

ISS 2019 is the first of seven conferences comprising SEMI’s inaugural Technology Leadership Series of the Americas. Aligned from coast to coast over one year, the series is designed to foster critical discussions on the short- and long-term influences and opportunities to the $2 trillion emerging markets.

ISS 2019 highlights include:

Keynotes

  • Dr. Jo de Boeck, chief strategy officer at IMEC, will share how nanotechnology’s “magic” will enable advanced applications for SMART mobility, SMART cities, infotainment and healthcare
  • Dr. Ann Kelleher, senior vice president for the technology and manufacturing group at Intel
  • Jim Talent, former U.S. Senator, will discuss the evolving U.S.-China strategic relationship

Economic trends and market perspectives affecting the chip industry

  • Executives and economists from Harvard Kennedy School, Gartner, Hilltop Economics, Linx, Amazon, Bank of America, Rockwell Automation, Ericsson, Selexis, Enthought and VLSI Research

Technology, manufacturing and industrial revolution discussions

  • Executives and CTOs from Google, TEL, Micron, Intel Labs, Applied Materials, Xperi, McKinsey, DECA Technologies, Carbon and Brewer Science

For more information about ISS, click here.

The semiconductor manufacturing industry is fighting to attract, educate, and retain the necessary talent for its continued growth. A significant workforce gap of up to 10,000 global positions stretches the industry’s ability to meet the world’s already demanding technology needs. To solve this challenge, SEMI, the global electronics manufacturing association, is launching an audacious and innovative campaign to raise industry awareness and attract students and recent graduates that don’t yet know about the immense opportunities available to them in semiconductor manufacturing.

Semiconductors are the brains and memory of all modern electronics. Their incredible processing power has made breakthroughs possible in communication, transportation, and medicine, powering everything from smartphones to space travel. Whether you’re driving a car, surfing the internet or using a computer, semiconductors drive technological innovation. Global semiconductor revenue has grown by over $100 billion in the last four years and is projected to surpass $0.5 trillion by 2019.

The campaign, You’re Welcome, speaks to how fundamental, yet underappreciated, this technology is. It includes a suspenseful, action-filled movie trailer that shows what happens when scientists, engineers, and mathematicians make semiconductors to save the world from the brink of disaster. The video also takes viewers behind-the-scenes of a semiconductor facility, or fab, which brings together cutting-edge STEM fields to develop the world’s most advanced technology. The campaign’s website provides information about the value and production of semiconductors, as well as a career guide that showcases the wide variety of opportunities available with companies such as Intel, Samsung, Applied Materials, Tokyo Electron, and the more than 2,000 SEMI member companies.

The campaign is just one piece in SEMI’s comprehensive workforce development plan. The plan engages students as early-on as 4th grade, inspires and motivates them through high school and college, and provides pathways to professional careers, building a pipeline to fill the short-term and long-term needs of the industry. Through the You’re Welcome campaign, SEMI is addressing the increasingly urgent workforce need by taking a completely new, never-before-seen approach to talent recruitment by leveraging high-interest areas of entertainment, media and storytelling to excite students about the industry’s role in society.

Leti, a research institute at CEA Tech, has proven that RRAM-based ternary-content addressable memory (TCAM) circuits, featuring the most compact structure developed to date, can meet the performance and reliability requirements of multicore neuromorphic processors.

TCAM circuits provide a way to search large data sets using masks that indicate ranges. These circuits are, therefore, ideal for complex routing and big data applications, where an exact match is rarely necessary.  TCAM circuits allow searching for stored information by its content, as opposed to classic memory systems in which a memory cell’s stored information is retrieved by its physical address. They shorten the search time compared to classic memory-based search algorithms, as all the stored information is compared with the searched data in parallel, within a single clock cycle.

But conventional SRAM-based TCAM circuits are usually implemented with 16 CMOS transistors, which limits storage capacity of TCAMs to tens of Mbs in standard memory structures, and takes up valuable silicon real estate in neuromorphic computing spiking neural-network chips.

The breakthrough of the CEA-Leti project replaced SRAM cells with resistive-RAM (RRAM) in TCAM circuits to reduce the number of required transistors to two (2T), and to two RRAMs (2R), which is the most compact structure for these circuits produced to date. In addition, the RRAMs were fabricated on top of the transistors, which also consumed less area. This suggests such a 2T2R structure can decrease the required TCAM area by a factor of eight compared to the conventional 16-transistor TCAM structure.

But while using RRAMs in TCAM circuits significantly reduces both silicon chip area needed and power consumption, and guarantees similar search speed compared to CMOS-based TCAM circuits, this approach brings new challenges:

  • Circuit reliability is strongly dependent on the ratio between the ON and OFF states of the memory cells. RRAM-based TCAM reliability could be affected by the relatively low ON/OFF ratio (~10-100) with respect to the 16-transistor structure (~), and
  • RRAMs have a limited endurance with respect to CMOS transistors, which can affect the lifespan of the system.

Overcoming these challenges requires trade-offs:

  • The voltage applied during a search operation can be decreased, which improves system reliability. However, this also degrades system performance, e.g. slower searches, and
  • The limited endurance can be overcome by either decreasing the voltage applied during each search, or increasing the power used to program the TCAM cells beforehand. Both increase system endurance, while slowing searches.

The work, presented Dec. 4 at IEDM 2018 in a paper entitled, “In-depth Characterization of Resistive Memory-based Ternary Content Addressable Memories”, clarifies the link between RRAM electrical properties and TCAM performance with extensive characterizations of a fabricated RRAM-based circuit.

The research showed a trade-off exists between TCAM performance (search speed) and TCAM reliability (match/mismatch detection and search/read endurance). This provides insights into programming RRAM-based TCAM circuits for other applications, such as network packets routing.

“Assuming many future neuromorphic computing architectures will have thousands of cores, the non-volatility feature of the proposed TCAM circuits will provide an additional crucial benefit, since users will have to upload all the configuration bits only the first time the network is configured,” said Denys R.B. Ly, a Ph.D. student at Leti and lead author of the paper. “Users will also be able to skip this potentially time-consuming process every time the chip is reset or power-cycled.”

A team of scientists from Arizona State University’s School of Molecular Sciences and Germany have published in Science Advances online today an explanation of how a particular phase-change memory (PCM) material can work one thousand times faster than current flash computer memory, while being significantly more durable with respect to the number of daily read-writes.

PCMs are a form of computer random-access memory (RAM) that store data by altering the state of the matter of the “bits”, (millions of which make up the device) between liquid, glass and crystal states. PCM technology has the potential to provide inexpensive, high-speed, high-density, high-volume, nonvolatile storage on an unprecedented scale.

The basic idea and material were invented by Stanford Ovshinsky, long ago, in1975, but applications have lingered due to lack of clarity about how the material can execute the phase changes on such short time scales and technical problems related to controlling the changes with necessary precision. Now high tech companies like Samsung, IBM and Intel are racing to perfect it.

The semi-metallic material under current study is an alloy of germanium, antimony and tellurium in the ratio of 1:2:4. In this work the team probes the microscopic dynamics in the liquid state of this PCM using quasi-elastic neutron scattering (QENS) for clues as to what might make the phase changes so sharp and reproducible.

On command, the structure of each microscopic bit of this PCM material can be made to change from glass to crystal or from crystal back to glass (through the liquid intermediate) on the time scale of a thousandth of a millionth of a second just by a controlled heat or light pulse, the former now being preferred. In the amorphous or disordered phase, the material has high electrical resistance, the “off” state; in the crystalline or ordered phase, its resistance is reduced 1000 fold or more to give the “on” state.

These elements are arranged in two dimensional layers between activating electrodes, which can be stacked to give a three dimension array with particularly high active site density making it possible for the PCM device to function many times faster than conventional flash memory, while using less power.

“The amorphous phases of this kind of material can be regarded as “semi-metallic glasses”,” explains Shuai Wei, who at the time was conducting postdoctoral research in SMS Regents’ Professor Austen Angell’s lab, as a Humboldt Foundation Fellowship recipient.

“Contrary to the strategy in the research field of “metallic glasses”, where people have made efforts for decades to slow down the crystallization in order to obtain the bulk glass, here we want those semi-metallic glasses to crystallize as fast as possible in the liquid, but to stay as stable as possible when in the glass state. I think now we have a promising new understanding of how this is achieved in the PCMs under study.”

A Deviation from the expected

Over a century ago, Einstein wrote in his Ph.D. thesis that the diffusion of particles undergoing Brownian motion could be understood if the frictional force retarding the motion of a particle was that derived by Stokes for a round ball falling through a jar of honey. The simple equation: D (diffusivity) = kBT/6??r where T is the temperature, ? is the viscosity and r is the particle radius, implies that the product D?/T should be constant as T changes, and the surprising thing is that this seems to be true not only for Brownian motion, but also for simple molecular liquids whose molecular motion is known to be anything but that of a ball falling through honey!

“We don’t have any good explanation of why it works so well, even in the highly viscous supercooled state of molecular liquids until approaching the glass transition temperature, but we do know that there are a few interesting liquids in which it fails badly even above the melting point,” observes Angell.

“One of them is liquid tellurium, a key element of the PCM materials. Another is water which is famous for its anomalies, and a third is germanium, a second of the three elements of the GST type of PCM. Now we are adding a fourth, the GST liquid itself..!!! thanks to the neutron scattering studies proposed and executed by Shuai Wei and his German colleagues, Zach Evenson (Technical University of Munich, Germany) and Moritz Stolpe (Saarland University, Germany) on samples prepared by Shuai with the help of Pierre Lucas (University of Arizona).”

Another feature in common for this small group of liquids is the existence of a maximum in liquid density which is famous for the case of water. A density maximum closely followed, during cooling, by a metal-to semiconductor transition is also seen in the stable liquid state of arsenic telluride, (As2Te3), which is first cousin to the antimony telluride (Sb2Te3 ) component of the PCMs all of which lie on the “Ovshinsky” line connecting antimony telluride (Sb2Te3 ) to germanium telluride (GeTe) in the three component phase diagram. Can it be that the underlying physics of these liquids has a common basis?

It is the suggestion of Wei and coauthors that when germanium, antimony and tellurium are mixed together in the ratio of 1:2:4, (or others along Ovshinsky’s “magic” line) both the density maxima and the associated metal to non-metal transitions are pushed below the melting point and, concomitantly, the transition becomes much sharper than in other chalcogenide mixtures.

Then, as in the much-studied case of supercooled water, the fluctuations associated with the response function extrema should give rise to extremely rapid crystallization kinetics. In all cases, the high temperature state (now the metallic state), is the denser.

“This would explain a lot,” enthuses Angell “Above the transition the liquid is very fluid and crystallization is extremely rapid, while below the transition the liquid stiffens up quickly and retains the amorphous, low-conductivity state down to room temperature. In nanoscopic “bits”, it then remains indefinitely stable until instructed by a computer-programmed heat pulse to rise instantly to a temperature where, on a nano-second time scale, it flash crystallizes to the conducting state, the “on” state.

Lindsay Greer at Cambridge University has made the same argument couched in terms of a “fragile-to-strong” liquid transition”.

A second slightly larger heat pulse can take the “bit” instantaneously above its melting point and then, with no further heat input and close contact with a cold substrate, it quenches at a rate sufficient to avoid crystallization and is trapped in the semi-conducting state, the “off” state.

“The high resolution of the neutron time of flight-spectrometer from the Technical University of Munich was necessary to see the details of the atomic movements. Neutron scattering at the Heinz Maier-Leibnitz Zentrum in Garching is the ideal method to make these movements visible,” states Zach Evenson.

SEMI, the global industry association representing the electronics manufacturing supply chain, today applauded the United States and China for agreeing to take first steps to reduce trade tensions. The U.S. plans to delay tariff increases on $200 billion worth of Chinese imports, China has vowed to increase U.S. market access, and both parties are planning talks over the course of 90 days to address current frictions.

“Everyone, businesses and consumers alike, relies on devices powered by semiconductors,” said Ajit Manocha, president and CEO of SEMI. “Tariffs on products threaten jobs, stifle innovation, curb growth, and compromise U.S. competitiveness.”

With intellectual property critical to the semiconductor industry, SEMI strongly supports efforts to better protect valuable IP. SEMI believes, however, that U.S. tariff increases will ultimately do nothing to change China’s trade practices. SEMI has long supported efforts to reduce and end trade tensions between the U.S. and China.

“While this is a first step, it is encouraging to see presidents Trump and Xi committed to working together,” Manocha said. “We look forward to continued negotiations that produce an agreement that not only removes tariffs altogether, but also satisfactorily addresses bilateral economic concerns.”

The semiconductor industry relies heavily on international trade. Since the tariffs have been in force, companies have faced higher costs, greater uncertainty, and difficulty selling products abroad.

Since action against China was announced in March, SEMI has engaged heavily with the Trump administration, submitting written comments and offering testimony on the importance of the free trade to the industry as well as the damaging effects of tariffs on Chinese goods. SEMI estimates that tariffs would have cost semiconductor companies more than $700 million annually.

Last month, SEMI issued “10 Principles for the Global Semiconductor Supply Chain in Modern Trade Agreements,” calling for their adoption in existing and new trade deals, including frameworks for a U.S.-China agreement.

In the face of the microelectronics industry’s unprecedented challenges and opportunities with artificial intelligence (AI) and new markets outside the historic semiconductor audiences, SEMI announces the Technology Leadership Series of the Americas. The seven-part sequence of related strategy and technical conferences comprises the world’s largest and most comprehensive approach for examining and fabricating future innovations that can fuel a higher quality of life for the planet.

As the era begins with the volume of the world’s data doubling every 12-18 months, a global brain trust of hundreds of industry experts has provided inputs for a coherent, step-by-step process that will position the microelectronics industry to navigate the future.

With an objective to reduce learning curves and shorten product times to market, key interest groups have rallied with SEMI in the past 24 months to multiply interactions with the supply chain. In turn, these exchanges are calculated to increase the members’ respective technical ROIs. Technology communities include the Fab Owners Alliance (FOA), FlexTech, MEMS & Sensors Industry Group (MSIG), Electronic System Design Alliance, as well as global partner associations such as IEEE and SAE International, which leads technical learning for the mobility industry.

As a result, more than 2,100 global market-related businesses have teamed with SEMI to help structure content for the Technology Leadership Series of the Americas.

Aligned from coast to coast, across a 12-month span, the series is designed to foster the most critical discussions for connecting both the short-term and long-term influences impacting the $2 trillion worth of emerging markets. The series further aims to remove guesswork about which of the world’s rapidly rising number of conferences provides the highest ROI for the senior executive, engineer-scientist and sales manager.

“There’s been lots of talk around AI, its potential enhancements for nearly all markets, and which priorities should be next for maximizing those. To facilitate measurable industry progress, the approach for this series is to fit together the most critical puzzle pieces – strategy, design, new materials and manufacturing technologies – that will deliver the most impactful roadmap for the coming decades,” said David Anderson, president of SEMI Americas and series co-author. “The experts have concluded that focal points identified for these topic-exclusive conferences will each serve as a stepping stone – or enabler – for the roadmap’s most important areas. As with previous industry efforts, what hasn’t changed is that the path to success hinges on collaboration by partners from across the supply chain.”

Target topics will address the leading edges of industry knowledge and practices, including up-to-the-minute market forecasts and deep dives into game-changing issues and advancements. Six strategy and technical conferences will culminate in an unmatched integration of technologies and partners at SEMICON West, July 9-11, 2019, in San Francisco.

The Series’ special conferences are:

  • Industry Strategy Symposium (ISS) Jan. 6-9 – will kick off the new year with analysis of new and emerging demand drivers for new architectures, new logic and memory, new streams of investment and how to advance their arrivals and ensure longevities that enable the next industrial revolution.
  • Flexible & Printed Electronics and MEMS & Sensors Technical Congress (FLEX/MSTC) Feb. 18-21 – the co-located events will provide the most comprehensive technical conference as FLEX focuses on the design and manufacture of flexible electronics, including sensors, IC integration and substrates, while MSTC focuses on the technology behind the trends in MEMS and sensors for autonomous mobility in mobile devices, IOT, drones, and autonomous transportations.
  • Advanced Semiconductor Manufacturing Conference (ASMC) May 6-9 – will improve the industry’s advanced manufacturing strategies and methodologies through a combined sharing of highlights and insights by device makers, equipment and materials suppliers and academics. Women in Semiconductors will hold their third annual workshop.
  • Strategic Materials Conference (SMC) Sept. 2019 – will share the latest developments from around the world in strategic materials that will be vital for new markets, system creation, heterogeneous integration and packaging.
  • MEMS & Sensors Executive Congress (MSEC) Oct. 2019 – will present how the next generations of MEMS and sensors will be designed and produced to meet on-going growth for emerging markets beyond the historic microelectronics customer base.
  • International Technology Partners Conference (ITPC) Nov. 3-6 – will advance productive trans-pacific relationships to help avoid threatened supply chain prosperity, leveraging thought-leadership and relationship-building programs for executive-level engagement.

At the peak of the collaborative series, SEMICON West 2019 will provide renowned global presenters and hands-on demos, at both strategic and technical levels, for up-to-minute predictions and breakthroughs on upcoming trends and enablers. Based on direction from SEMI’s members, the five vertical application areas of AI and Data, Smart Transportation, MedTech, Smart Manufacturing and Industrial Automation, plus workforce development, will be featured at the semiconductor industry’s flagship event.

The Semiconductor Industry Association (SIA), representing U.S. leadership in semiconductor manufacturing, design, and research, today announced the addition of Silicon Labs (NASDAQ: SLAB) as an SIA member. Silicon Labs President and CEO Tyson Tuttle was elected to the SIA board of directors at the association’s board meeting on Nov. 29. Silicon Labs joins several other companies that have become SIA members within the last year: Cree, NVIDIA, Xilinx, Arm, SK Hynix, and KLA-Tencor.

“Silicon Labs is a major player and leading voice in our industry, and we’re thrilled to have them in the SIA tent,” said John Neuffer, SIA President and CEO. “SIA has a 40-year history of advancing the semiconductor industry’s interests in Washington and capitals around the world. Our work to advance policies that will promote growth and innovation in our industry will be greatly strengthened by the addition of Silicon Labs as a member, and we are excited to welcome Tyson Tuttle to the SIA board.”

Tyson Tuttle has been instrumental in shaping Silicon Labs’ strategic and technological direction for more than 20 years. After becoming CEO in 2012, Tyson laid the foundation for a cultural shift to serve broad-based markets with a greater emphasis on software and tools, enabling customers to simplify IoT system design. As CEO, Tyson has transformed Silicon Labs into a leading provider of IoT connectivity solutions, with more than half of the company’s revenue stemming from the IoT. He has more than 25 years of semiconductor experience and holds more than 70 patents in RF and mixed-signal IC design. Tyson received a B.S. degree in Electrical Engineering in 1989 from Johns Hopkins University and an M.S. degree in Electrical Engineering in 1992 from UCLA.

“Smart government policy is critical to the continued strength of the semiconductor industry, the tech sector, and the broader economy,” said Tuttle. “It is a true pleasure to represent Silicon Labs on the SIA board and to work alongside my colleagues to make meaningful progress on issues of great importance to us all.”

Researchers from Intel Corp. and the University of California, Berkeley, are looking beyond current transistor technology and preparing the way for a new type of memory and logic circuit that could someday be in every computer on the planet.

In a paper appearing online Dec. 3 in advance of publication in the journal Nature, the researchers propose a way to turn relatively new types of materials, multiferroics and topological materials, into logic and memory devices that will be 10 to 100 times more energy-efficient than foreseeable improvements to current microprocessors, which are based on CMOS (complementary metal-oxide-semiconductor).

Single crystals of the multiferroic material bismuth-iron-oxide. The bismuth atoms (blue) form a cubic lattice with oxygen atoms (yellow) at each face of the cube and an iron atom (gray) near the center. The somewhat off-center iron interacts with the oxygen to form an electric dipole (P), which is coupled to the magnetic spins of the atoms (M) so that flipping the dipole with an electric field (E) also flips the magnetic moment. The collective magnetic spins of the atoms in the material encode the binary bits 0 and 1, and allow for information storage and logic operations. Credit: Ramamoorthy Ramesh lab, UC Berkeley

The magneto-electric spin-orbit or MESO devices will also pack five times more logic operations into the same space than CMOS, continuing the trend toward more computations per unit area, a central tenet of Moore’s Law.

The new devices will boost technologies that require intense computing power with low energy use, specifically highly automated, self-driving cars and drones, both of which require ever increasing numbers of computer operations per second.

“As CMOS develops into its maturity, we will basically have very powerful technology options that see us through. In some ways, this could continue computing improvements for another whole generation of people,” said lead author Sasikanth Manipatruni, who leads hardware development for the MESO project at Intel’s Components Research group in Hillsboro, Oregon. MESO was invented by Intel scientists, and Manipatruni designed the first MESO device.

Transistor technology, invented 70 years ago, is used today in everything from cellphones and appliances to cars and supercomputers. Transistors shuffle electrons around inside a semiconductor and store them as binary bits 0 and 1.

In the new MESO devices, the binary bits are the up-and-down magnetic spin states in a multiferroic, a material first created in 2001 by Ramamoorthy Ramesh, a UC Berkeley professor of materials science and engineering and of physics and a senior author of the paper.

“The discovery was that there are materials where you can apply a voltage and change the magnetic order of the multiferroic,” said Ramesh, who is also a faculty scientist at Lawrence Berkeley National Laboratory. “But to me, ‘What would we do with these multiferroics?’ was always a big question. MESO bridges that gap and provides one pathway for computing to evolve”

In the Nature paper, the researchers report that they have reduced the voltage needed for multiferroic magneto-electric switching from 3 volts to 500 millivolts, and predict that it should be possible to reduce this to 100 millivolts: one-fifth to one-tenth that required by CMOS transistors in use today. Lower voltage means lower energy use: the total energy to switch a bit from 1 to 0 would be one-tenth to one-thirtieth of the energy required by CMOS.

“A number of critical techniques need to be developed to allow these new types of computing devices and architectures,” said Manipatruni, who combined the functions of magneto-electrics and spin-orbit materials to propose MESO. “We are trying to trigger a wave of innovation in industry and academia on what the next transistor-like option should look like.”

Internet of things and AI

The need for more energy-efficient computers is urgent. The Department of Energy projects that, with the computer chip industry expected to expand to several trillion dollars in the next few decades, energy use by computers could skyrocket from 3 percent of all U.S. energy consumption today to 20 percent, nearly as much as today’s transportation sector. Without more energy-efficient transistors, the incorporation of computers into everything – the so-called internet of things – would be hampered. And without new science and technology, Ramesh said, America’s lead in making computer chips could be upstaged by semiconductor manufacturers in other countries.

“Because of machine learning, artificial intelligence and IOT, the future home, the future car, the future manufacturing capability is going to look very different,” said Ramesh, who until recently was the associate director for Energy Technologies at Berkeley Lab. “If we use existing technologies and make no more discoveries, the energy consumption is going to be large. We need new science-based breakthroughs.”

Paper co-author Ian Young, a UC Berkeley Ph.D., started a group at Intel eight years ago, along with Manipatruni and Dmitri Nikonov, to investigate alternatives to transistors, and five years ago they began focusing on multiferroics and spin-orbit materials, so-called “topological” materials with unique quantum properties.

“Our analysis brought us to this type of material, magneto-electrics, and all roads led to Ramesh,” said Manipatruni.

Multiferroics and spin-orbit materials

Multiferroics are materials whose atoms exhibit more than one “collective state.” In ferromagnets, for example, the magnetic moments of all the iron atoms in the material are aligned to generate a permanent magnet. In ferroelectric materials, on the other hand, the positive and negative charges of atoms are offset, creating electric dipoles that align throughout the material and create a permanent electric moment.

MESO is based on a multiferroic material consisting of bismuth, iron and oxygen (BiFeO3) that is both magnetic and ferroelectric. Its key advantage, Ramesh said, is that these two states – magnetic and ferroelectric – are linked or coupled, so that changing one affects the other. By manipulating the electric field, you can change the magnetic state, which is critical to MESO.

The key breakthrough came with the rapid development of topological materials with spin-orbit effect, which allow for the state of the multiferroic to be read out efficiently. In MESO devices, an electric field alters or flips the dipole electric field throughout the material, which alters or flips the electron spins that generate the magnetic field. This capability comes from spin-orbit coupling, a quantum effect in materials, which produces a current determined by electron spin direction.

In another paper that appeared earlier this month in Science Advances, UC Berkeley and Intel experimentally demonstrated voltage-controlled magnetic switching using the magneto-electric material bismuth-iron-oxide (BiFeO3), a key requirement for MESO.

“We are looking for revolutionary and not evolutionary approaches for computing in the beyond-CMOS era,” Young said. “MESO is built around low-voltage interconnects and low-voltage magneto-electrics, and brings innovation in quantum materials to computing.”