SystemX Alliance Newsletter - September 2021

SystemX 2021 Virtual Fall Conference

Save the Date! - November 8-11, 2021

Due to COVID-19 restrictions, this year's SystemX Fall Conference will be held virtually. Though we cannot be all together on campus again this year, we hope this LIVE (virtual) format can be the next best thing!

We will hold a live student e-poster session on Gather.town on Monday, November 8th. This is followed by our live focus area technical sessions on Zoom on Tuesday-Thursday, November 9-11th.

We hope that this virtual format will allow for engagement and participation, even from our members from all around the globe! All final schedules, logistical information, and updates will be up on the SystemX Fall Conference page. For information on how to register, please contact Kiyah Agtarap (kagtarap@stanford.edu).

SystemX 2021 Spring Workshop - "Can Stanford University help solve the global semiconductor crisis?"

Tom Abate | Stanford Engineering

With the U.S. poised to invest $50 billion in chip technologies, researchers prepare to create an infrastructure to accelerate how lab discoveries become practical technologies.

Found in virtually every gadget powered by batteries or electricity, so ubiquitous as to be taken for granted, is that bedrock of our technological era, the semiconductor chip.

But last year, when automotive assembly lines stalled for lack of chips to build everything from anti-lock brakes to automatic door locks, public officials began to recognize the crisis that research and industrial scientists had seen coming.

“The world isn’t just facing production shortages for the chips we rely on today,” said Stanford electrical engineering Professor H.-S. Philip Wong. “We aren’t moving fast enough to create the next generation of semiconductors that we’ll need to broaden educational and economic opportunities, conserve energy and natural resources, and provide better and fairer access to technology.”

That sense of urgency and excitement suffused a recent virtual conference hosted by Stanford’s SystemX Alliance, which has, in various incarnations over the last 40 years, brought academic and industrial researchers together to develop new chip technologies and systems built on them. Prominent leaders of companies and academia presented visions for future generations of semiconductor technologies that will meet the insatiable demands for broadly accessible, energy-efficient computing. In many ways, Wong said, what we are seeing is less a crisis, but rather a huge opportunity.

The June event – Future Directions of Semiconductor Technology – was held as the Senate passed, and the House of Representatives is poised to take up, a bill that President Joe Biden is eager to sign that will invest roughly $50 billion in new fabs, or semiconductor fabrication plants, as well as fund research into developing new chip technologies and applications.

The bipartisan consensus to boost the chip sector, which first emerged during the previous administration, gathered force as the auto plant shutdowns caught lawmakers’ attention and the Biden administration began to define infrastructure as silicon and circuitry as well as concrete and steel.

Wong said Stanford could help lead on an initiative that will emerge from this chip stimulus act – creating a national “lab to fab” infrastructure to reduce the friction that hampers translation of academic discoveries into practical technologies. Until now, the U.S. has relied on startups to commercialize discoveries, but as electronic systems become ever more complex, the costs and time of this scale-up process are impeding innovation.

“Fragments of lab-to-fab translation processes exist in other places around the world, but they are conspicuously absent in the United States,” Wong said.

Read the full article here: Stanford Engineering | by Tom Abate | July 08, 2021

To view the recordings and PDF slides from the 2021 Spring Workshop, visit the SystemX Spring Workshop page.

Stanford Electrical Engineering's 125th Anniversary

Video presentations from the event are available

The Electrical Engineering Department celebrated its 125th anniversary event in 2019, which involved invited faculty and alumni speakers who shared their experiences and thoughts on the past, present, and future of the department. 

These video presentations are available for viewing on the EE YouTube channel and also can be found listed on the EE website here: https://ee.stanford.edu/news/department-news/02-05-2020/ee125-anniversary-event-videos

Plastic Memory Could Boost Flexible Electronics - New phase-change memory needs less energy, partly because it's built on plastic

Samuel K. Moore | IEEE Spectrum

For stick-on displays, smart bandages, and cheap flexible plastic sensors to really take off, they'll need some way of storing data for the long-term that can be built on plastic. "In the ecosystem of flexible electronics, having memory options is very important," says Stanford electrical engineering professor Eric Pop.

But versions of today's non-volatile memories, such as Flash, aren't a great fit. So when Pop and his team of engineers decided to try adapting a type of phase-change memory to plastic, they figured it would be a long shot. What they came up with was a surprise—a memory that actually works better because it's built on plastic. The energy needed to reset the memory, a critical feature for this type of device, is an order of magnitude lower than previous flexible versions. They reported their findings this week in Science.

Phase-change memory (PCM) is not an obvious win for plastic electronics. It stores its bit as a resistive state. In its crystalline phase, it has a low resistance. But running enough current through the device melts the crystal, allowing it to then freeze in an amorphous phase that is more resistive. The process is reversible. Importantly, especially for experimental neuromorphic systems, PCM can store intermediate levels of resistance. So a single device can store more than one bit of data.

Unfortunately, the usual set of materials involved doesn't work well on flexible substrates like plastic. The problem is "programming current density": Basically, how much current do you need to pump through a given area in order to heat it up to the temperature at which the phase change takes place? The uneven surface of bendy plastic means PCM cells using the usual materials can't be made as small as they are on silicon, requiring more current to achieve the same switching temperature.

Think of it as trying to bake a pie in an oven with the door slightly ajar. It will work, but it takes a lot more time and energy. Pop and his colleagues were looking for a way to close the oven door.

They decided to try a material called a superlattice, crystals made from repeating nanometers-thick layers of different materials. Junji Tominaga and researchers at the National Institute of Applied Industrial Science and Technology in Tsukuba, Japan had reported promising results back in 2011 using a superlattice composed of germanium, antimony, and tellurium. Studying these superlattices, Pop and his colleagues concluded that they should be very thermally insulating, because in its crystalline form there are atomic-scale gaps between the layers. These "van der Waals-like gaps" restrict both the flow of current and, crucially, heat. So when current is forced through, the heat doesn't quickly drain away from the superlattice, and that means it takes less energy to switch from one phase to another.

But the superlattice work was hardly a slam dunk. "We started working on it several years ago, but we really struggled and almost gave up," says Pop. The superlattice works if the van der Waals gaps are oriented parallel to each other and without major mixing between layers, Pop explains. But the peculiarities of the material deposition equipment involved mean that "just because they published their parameters in Japan, doesn't mean you can use them in a tool in Palo Alto."

Asir Intisar Khan, a doctoral candidate working with Pop, had to push through a trial-and-error process that involved more than 100 attempts to produce superlattices with the right van der Waals gaps.

The researchers kept the heat in the memory device by confining the flow of current to a 600-nanometer-wide pore-like structure that was surrounded by insulating aluminum oxide. The final layer of insulation was the plastic itself, which resists the flow of heat considerably better than the silicon PCM is usually built on. The completed device had a current density of about 0.1 mega-amperes per square centimeter, about two orders of magnitude lower than conventional PCM on silicon and an order of magnitude better than previous flexible devices. Furthermore, it showed four-stable resistance states. So it can store multiple bits of data in a single device.(Photo: A superlattice structure formed by alternating layers of antimony telluride and germanium telluride. Van der Waals-like gaps form between the layers, restricting the flow of current and heat. | K. YAMAMOTO AND A.I. KHAN)

That building the device on plastic would actually improve things wasn't something the team had planned. Alwin Daus, a post-doctoral researcher in the lab with flexible electronics expertise, says the team assumed that the titanium nitride electrode between the superlattice and the substrate would limit heat loss and thus the substrate would not influence the memory operation. But later simulations confirmed that heat penetrates into the plastic substrate, which has a low thermal conductivity compared to silicon substrates.

The work reported this week is a proof of concept for low-power storage on flexible surfaces, Khan says. But the importance of thermal insulation applies to silicon devices as well. The team hopes to improve the devices by further shrinking the pore diameter and by making the sides of the device more insulating. Simulations already show that making the aluminum oxide walls thicker reduces the current needed to reach the switching temperature.The researchers will also look into other superlattice structures that might have even better properties.

Read article here: IEEE Spectrum | by Samuel K. Moore | September 09, 2021

Upcoming EE310/SystemX Seminars

View the 2021 Fall Quarter speaker lineup:

Fall Quarter 2021 Speaker List with Lecture Topics:

• Integrated Multi-wavelength Control of Ion Qubits - Robert Niffenegger, MIT Lincoln Labs
• Digital Wellness in an Analog World - Roger Nichols, Keysight Technologies
• Aluminum Scandium Nitride Microdevices for Next Generation Nonvolatile Memory and Microelectromechanical Systems - Troy Olsson, University of Pennsylvania
• Photonic quantum computing - Zachary Vernon, Xanadu
• Silicon quantum dot technology for quantum computing - Florian Luthi, Intel
• 2D devices enabling flexible electronics applications - Alwin Daus, Stanford University
• Augmented reality (AR) technology challenges and directions - Bernard Kress, Microsoft
• 5G-enabled drones and robotics - Mac Schwager, Stanford University
• Cryptocurrency challenges and directions - Dan Boneh, Stanford University
• Merging technology and performance art - Catie Cuan, Stanford University
• Autonomous miniature distributed space systems - Simone D'Amico, Stanford University

To receive seminar announcement emails (with livestream information), please subscribe to the SystemX Seminar Mailing List. To view past seminar recordings, visit the SystemX Website Seminar page (login required).

Additional questions: Jon Candelaria, SystemX Seminar Instructor (jjcandel@stanford.edu)

Priyanka Raina recognized as an Intel Rising Star Faculty, 2021

Stanford Electrical Engineering

Congratulations to Professor Priyanka Raina for being recognized as an Intel 2021 Rising Star Faculty. The Intel® Rising Star Faculty Award (RSA) program has selected ten promising early-career academic researchers who lead some of the most important technology research of our time. The chosen faculty members work with disruptive technologies that have the potential to advance the future of computing in fields encompassing computer science, electrical engineering, computer engineering, material science, and chemical engineering.

The program recognizes community members who are doing exceptional work in the field and facilitates long-term collaborative relationships with senior technical leaders at Intel. Recipients of this award are also distinguished for exemplifying innovative teaching methods and increasing the participation of women and underrepresented minorities in computer science and engineering.

The key technology areas under investigation by selected faculty include cybersecurity, hardware security, nanotechnology, semiconductor device technologies, neuromorphic computing, machine learning/artificial intelligence, and memory management.

This year's winners include esteemed faculty at the following institutions:

• Carnegie Mellon University
• University of Illinois at Urbana-Champaign
• Arizona State University
• Stanford University
• University of Texas at Austin
• Cornell University
• University of Pennsylvania
• Oregon State University
• Georgia Institute of Technology
• Indian Institute of Science

Please join us in congratulating Priyanka and all the RSA winners for 2021!

Excerpted from "Intel 2021 Rising Star Faculty Award..."

Priyanka Raina recognized as an Intel Rising Star Faculty, 2021 - Electrical Engineering Department - September 2021

Students & Faculty Awards/Recognitions

Katie Antilla (Advisor: Prof. Shan Wang) is a recipient of an ARCS Scholar Award  for the 2021-22 academic year

Prof. Clark Barrett won the 2021 CAV Award and the 2021 LICS Test-of-Time Award

Jonathon Fagert (Advisor: Prof. Hae Young Noh) won the Best Paper Award, Society for Experimental Mechanics (SEM) at the IMAC XXXIX A Conference and Exposition on Structural Dynamics, Dynamics of Civil Structures Technical Division (SEM IMAC 2021)

Prof. Doug James won the 2021 Computer Graphics Achievement Award

Prof. Christos Kozyrakis won the Best Paper Award at the Usenix ATC Conference

Justin Kruger, Katie Wallace, Adam Koenig, and Prof. Simone D'Amico won the M. Charles Fogg Best Paper Award at the 2021 IEEE Aerospace Conference for their paper titled Autonomous Angles-Only Navigation for Spacecraft Swarms around Planetary Bodies

Jingxiao Liu (Advisor: Prof. Hae Young Noh) won the Best Journal Paper Runner-up Award at the ASME Structural Health Monitoring & NDE Technical Committee (2021) and won Third Place at the Student Paper Competition at the ASCE Engineering Mechanics Institute Structural Health Monitoring and Control Committee (ASCE EMI 2021)

Brendan Marsh (Advisor: Prof. Benjamin Lev) won one of the two Q-FARM Fellowships awarded each year to Stanford PhD students

Tara Mina (Advisor: Prof. Grace Gao) won the Zonta International Amelia Earhart Fellowship

Prof. Subhasish Mitra awarded 2021 SIA-SRC University Researcher Award

Prof. Boris Murmann awarded 2021 SIA-SRC University Researcher Award

Ana Sofia de Olazarra (Advisor: Prof. Shan Wang) was awarded a Bio-X Stanford Interdisciplinary Graduate Fellowship

Prof. Juan G. Santiago won the AES Lifetime Achievement Award by the AES Electrophoresis Society

Prof. Krishna Saraswat awarded the Semiconductor Research Corporation's (SRC) Aristotle Award

Prof. Krishna Shenoy renews his Howard Hughes Medical Institute (HHMI) Investigatorship

Prima Dewi Sinawang (Advisor: Prof. Utkan Demirci) receives Cancer Imaging and Early Detection Program Award

Sergey Stavisky (Advisor: Dr. Jaimie Henderson) won the 2021 Regeneron Prize for Creative Innovation