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Posts Tagged ‘MIT’

Photonics in Silicon R&D Toward Tb/s

Tuesday, January 3rd, 2017

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By Ed Korczynski, Sr. Technical Editor

The client:server computing paradigm colloquially referred to as the “Cloud” results in a need for extremely efficient Cloud server hardware, and from first principles the world can save a lot of energy resources if servers run on photonics instead of electronics. Though the potential for cost-savings is well known, the challenge of developing cost-effective integrated photonics solutions remains. Today, discrete compound-semiconductor chips function as transmitters, multiplexers (MUX), and receivers of photons, while many global organizations pursue the vision of lower-cost integrated silicon (Si) photonics circuits.

Work on photonics chips—using light as logic elements in an integrated circuit—built in silicon (Si) has accelerated recently with announcements of new collaborative research and development (R&D) projects. Leti, an institute of CEA Tech, announced the launch of a European Commission Horizon 2020 “COSMICC” project to enable mass commercialization of Si-photonics-based transceivers to meet future data-transmission requirements in data centers and super computing systems.

The Leti-coordinated COSMICC project will combine CMOS electronics and Si-photonics with innovative fiber-attachment techniques to achieve 1 Tb/s data rates. These scalable solutions will provide performance improvement an order of magnitude better than current VCSELs transceivers, and the COSMICC-developed technology will address future data-transmission needs with a target cost per bit that traditional wavelength-division multiplexing (WDM) transceivers cannot meet. The project’s 11 partners from five countries are focusing on developing mid-board optical transceivers with data rates up to 2.4 Tb/s with 200 Gb/s per fiber using 12 fibers. The devices will consume less than 2 pJ/bit. and cost approximately 0.2 Euros/Gb/s.

Figure 1: Schematic of COSMICC on-board optical transceiver at 2.4 Tb/s using 50 Gbps/wavelength, 4 CWDM wavelengths per fiber, 12 fibers for transmission and 12 fibers for reception. (Source: Leti)

A first improvement will be the introduction of a silicon-nitride (SiN) layer that will allow development of temperature-insensitive MUX/DEMUX devices for coarse WDM operation, and will serve as an intermediate wave-guiding layer for optical input/output. The partners will also evaluate capacitive modulators, slow-wave depletion modulators with 1D periodicity, and more advanced approaches. These include GeSi electro-absorption modulators with tunable Si composition and photonic crystal electro-refraction modulators to make micrometer-scale devices. In addition, a hybrid III-V on Si laser will be integrated in the SOI/SiN platform in the more advanced transmitter circuits.

Meanwhile in the United States, Coventor, Inc. is collaborating with the Massachusetts Institute of Technology (MIT) on photonics modeling. MIT is a key player in the AIM Photonics program, a federally funded, public-private partnership established to advance domestic capabilities in integrated photonic technology and strengthen high-tech U.S.-based manufacturing. Coventor will provide its SEMulator3D process modeling platform to model the effect of process variation in the development of photonic integrated components.

“Coventor’s technical expertise in predicting the manufacturability of advanced technologies is outstanding. Our joint collaboration with Coventor will help us develop new design methods for achieving high yield and high performance in integrated photonic applications,” said Professor Duane Boning of MIT. Boning is an expert at modeling non-linear effects in processing, many years after working on the semiconductor industry’s reference model for the control of chemical-mechanical planarization (CMP) processing.

—E.K.

Research Alert: March 4, 2014

Tuesday, March 4th, 2014

SRC and MIT extend high-resolution lithography

MIT researchers sponsored by Semiconductor Research Corporation have introduced new directed self-assembly (DSA) techniques that promise to help semiconductor manufacturers develop more advanced and less expensive components.

The MIT study demonstrates that complex patterns of lines, bends and junctions with feature sizes below 20nm can be made by block copolymer self-assembly guided by a greatly simplified template. This study explained how to design the template to achieve a desired pattern. Electron-beam lithography was used to produce the template serially, while the block copolymer filled in the rest of the pattern in a parallel process. This hybrid process can be five or more times faster than writing the entire pattern by electron beam lithography.

sembly to produce dense, high resolution patterns was proposed and demonstrated several years ago, but there was no systematic way to design templates to achieve a complex block copolymer pattern. The MIT study developed a simple way to design a template to achieve a specific block copolymer pattern over a large area. Although the work used electron-beam lithography to define the template, other methods such as photolithography with trimming could be used to produce the templates.

Block copolymer lithography is already on the semiconductor industry roadmap as directed self-assembly, but the process is still in its infancy. Although DSA patterning has been demonstrated on 300 millimeter wafers, these early trials used templates fabricated by photolithography with limited resolution and limited control of the feature geometry. The MIT process offers a path to far more complicated geometries using relatively simple templates. Next steps involve the research being shared with semiconductor companies for further studies.

How 19th century physics could change the future of nanotechnology

Researchers at the University of Cincinnati have found that their unique method of light-matter interaction analysis appears to be a good way of helping make better semiconductor nanowires.

“Semiconductor nanowires are one of the hottest topics in the nanoscience research field in the recent decade,” says Yuda Wang, a UC doctoral student. “Due to the unique geometry compared to conventional bulk semiconductors, nanowires have already shown many advantageous properties, particularly in novel applications in such fields as nanoelectronics, nanophotonics, nanobiochemistry and nanoenergy.”

Wang will present the team’s research “Transient Rayleigh Scattering Spectroscopy Measurement of Carrier Dynamics in Zincblende and Wurtzite Indium Phosphide Nanowires” at the American Physical Society (APS) meeting to be held March 3-7 in Denver. Nearly 10,000 professionals, scholars and students will attend the APS meeting to discuss new research from industry, universities and laboratories from around the world.

Key to this research is UC’s new method of Rayleigh scattering, a phenomenon first described in 1871 and the scientific explanation for why the sky is blue in the daytime and turns red at sunset. The researchers’ Rayleigh scattering technique probes the band structures and electron-hole dynamics inside a single indium phosphide nanowire, allowing them to observe the response with a time resolution in the femtosecond range – or one quadrillionth of a second.

JILA physicists discover “quantum droplet” in semiconductor

JILA physicists used an ultrafast laser and help from German theorists to discover a new semiconductor quasiparticle—a handful of smaller particles that briefly condense into a liquid-like droplet.

Quasiparticles are composites of smaller particles that can be created inside solid materials and act together in a predictable way. A simple example is the exciton, a pairing, due to electrostatic forces, of an electron and a so-called “hole,” a place in the material’s energy structure where an electron could be, but isn’t.

The new quasiparticle, described in the Feb. 27, 2014, issue of Nature and featured on the journal’s cover, is a microscopic complex of electrons and holes in a new, unpaired arrangement. The researchers call this a “quantum droplet” because it has quantum characteristics such as well-ordered energy levels, but also has some of the characteristics of a liquid. It can have ripples, for example. It differs from a familiar liquid like water because the quantum droplet has a finite size, beyond which the association between electrons and holes disappears.

Although its lifetime is only a fleeting 25 picoseconds (trillionths of a second), the quantum droplet is stable enough for research on how light interacts with specialized forms of matter.

The JILA team created the new quasiparticle by exciting a gallium-arsenide semiconductor with an ultrafast red laser emitting about 100 million pulses per second. The pulses initially form excitons, which are known to travel around in semiconductors. As laser pulse intensity increases, more electron-hole pairs are created, with quantum droplets developing when the exciton density reaches a certain level. At that point, the pairing disappears and a few electrons take up positions relative to a given hole. The negatively charged electrons and positively charged holes create a neutral droplet. The droplets are like bubbles held together briefly by pressure from the surrounding plasma.

Solid State Watch: February 21-28, 2014

Friday, February 28th, 2014
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The Week In Review: February 28, 2014

Friday, February 28th, 2014

MIT researchers sponsored by Semiconductor Research Corporation have introduced new directed self-assembly (DSA) techniques that promise to help semiconductor manufacturers develop more advanced and less expensive components.

Renesas Electronics Corporation unveiled the RX64M Group of microcontrollers (MCUs), its first product in the flagship RX Family of 32-bit MCUs to be fabricated in a 40nm process.

EV Group and Brisbane Materials Technology introduced a new anti-reflective (AR) coating solution based on BMT’s innovative XeroCoat materials. The jointly developed manufacturing solution enables lumen output increases of up to eight percent.  The AR coating manufacturing solution can be seamlessly integrated with established production schemes, allowing the coating of LED components at room temperature and atmospheric pressure.

International Rectifier, IR, announced that the company has commenced initial production at its new ultra-thin wafer processing facility in Singapore (IRSG). Wafer thinning, metallization, testing and additional proprietary wafer level processing are undertaken at the new 60,000 square foot manufacturing site which receives processed wafers from IR’s internal fabs and foundry partners. The facility, which will employ approximately 135 people in the initial phase, will process a variety of products, including the company’s latest generation power MOSFETs and IGBTs.

PLACYD, an EU funded consortium of industrial and academic collaborators and led by Arkema will establish a dedicated material manufacturing facility that allows the production of block copolymers meeting the rigorous standards required for their use in industry as nanolithographic templates.  PLACYD brings together researchers and industries to allow for the first time the integration of synthesis through to wafer scale production and system/device characterization. Partners include: CEA-Leti, STMicroelectronics, Intel IPLS, Mentor Graphics, ASML and other leading EU companies and research organizations.

JILA physicists used an ultrafast laser and help from German theorists to discover a new semiconductor quasiparticle—a handful of smaller particles that briefly condense into a liquid-like droplet. Quasiparticles are composites of smaller particles that can be created inside solid materials and act together in a predictable way. A simple example is the exciton, a pairing, due to electrostatic forces, of an electron and a so-called “hole,” a place in the material’s energy structure where an electron could be, but isn’t.