Showing posts with label CNT. Show all posts
Showing posts with label CNT. Show all posts

Tuesday, October 6, 2020

Imec demonstrates CNT pellicle utilization on EUV scanner

LEUVEN (Belgium, LINK) October 6, 2020 — Imec, a world-leading research and innovation hub in nanoelectronics and digital technologies, announced today promising results in extreme ultraviolet (EUV) reticle protection. Multiple CNT-based pellicles were mounted on reticles and exposed in the NXE:3300 EUV scanner at imec, demonstrating the successful fabrication and scanner handling of full-field CNT-based pellicles. The tested pellicles had a single-pass EUV transmission up to 97%. The impact on imaging was found to be low and correctable based on critical dimension (CD), dose, and transmission measurements.

A pellicle is a membrane used to protect the photomask from contamination during high-volume semiconductor manufacturing. It is mounted a few millimeters above the surface of the photomask so that if particles land on the pellicle, they will be too far out of focus to print. Developing such an EUV pellicle is very challenging, since 13.5nm light is absorbed by most materials. In addition, stringent thermal, chemical, and mechanical requirements must be achieved. Such highly transparent pellicle is critical to enable high yield and throughput in advanced semiconductor manufacturing. 

Imec demonstrates a CNT Pelicle (photo

Imec has leveraged partners in the semiconductor industry, materials companies and fundamental research to develop an innovative EUV pellicle design with potential to survive scanner powers beyond 600 Watts

“Imec has leveraged partners in the semiconductor industry, materials companies and fundamental research to develop an innovative EUV pellicle design with potential to survive scanner powers beyond 600 Watts,” said Emily Gallagher, principal member of technical staff at imec. “We have seen tremendous progress in carbon nanotube membrane development in the past year and, based on strong collaborations with our partners, are confident it will result in a high-performance pellicle solution in the near future.”

CNTs are one-atom-thick carbon sheets rolled into tubes. The CNTs can be single-, double- or multi-walled and can vary in diameter and in length. These engineered CNTs can be arranged in different configurations to form membranes of different densities. Since 2015, imec has been working with selected CNT suppliers (Canatu Oy and Lintec of America, Inc., Nano-Science & Technology Center) to develop membranes that meet the EUV pellicle targets for properties like transmittance, thermal durability, permeability, and strength and to enable the imaging results reported today. Future work will focus on achieving acceptable lifetimes for high volume manufacturing of these pellicles in scanners.

Saturday, December 3, 2016

Russian and Finnish scientists fabricate ZnO ALD coated SWCNTs p-type field effect transistors

TASS reports: Russian scientists create carbon nanotubes coated with zinc oxide 

Researchers from Skoltech, Aalto University, and Peter the Great St. Petersburg Polytechnic University have successfully demonstrated the technique of coating zinc oxide on the surface of single-walled carbon nanotubes, the SPbPU’s press-service said. Based on the new material, ambipolar field transistors have been maintained which may find their applications in logic circuits and memory cells.

Please find the abstract below to a joint publication in Nanotechnology.


Single-walled carbon nanotubes coated with ZnO by atomic layer deposition

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Nanotechnology, Volume 27,Number 48

The possibility of ZnO deposition on the surface of single-walled carbon nanotubes (SWCNTs) with the help of an atomic layer deposition (ALD) technique was successfully demonstrated. The utilization of pristine SWCNTs as a support resulted in a non-uniform deposition of ZnO in the form of nanoparticles. To achieve uniform ZnO coating, the SWCNTs first needed to be functionalized by treating the samples in a controlled ozone atmosphere. The uniformly ZnO coated SWCNTs were used to fabricate UV sensing devices. An UV irradiation of the ZnO coated samples turned them from hydrophobic to hydrophilic behaviour. Furthermore, thin films of the ZnO coated SWCNTs allowed us switch p-type field effect transistors made of pristine SWCNTs to have ambipolar characteristics.

Monday, April 18, 2016

ALD and CNT template produces sub-5 nm features

As reported by : Researchers at Korea University are reporting on a new way to make nano-trenches less than 5 nm deep with a technique called atomic-layer deposition (ALD), and single-walled carbon nanotubes as templates. The structures produced could be used to make high-density resistive components for a wide range of nanoelectronics devices.

Full story here

(a) Schematic diagram representing the creation of SiO2 nano-trenches. AFM image of (b) nano-trenches after further reactive ion etch of SiO2 through an alumina mask, and (c) SiO2 nano-trenches obtained by an additional etching in RIE and wet etching of alumina. Courtesy: Nanotechnology

Sunday, April 17, 2016

Tesla coil causes carbon nanotubes to self-assemble into long wire

This is a cool must watch video on self assembly of carbon nano tubes into long wires from researchers at Rice University. HOUSTON – (April 14, 2016) – Scientists at Rice University have discovered that the strong force field emitted by a Tesla coil causes carbon nanotubes to self-assemble into long wires, a phenomenon they call “Teslaphoresis.”

 The team led by Rice chemist Paul Cherukuri reported its results this week in ACS Nano. - See more at:

Teslaphoresis of Carbon Nanotubes

Lindsey R. Bornhoeft, Aida C. Castillo, Preston R. Smalley, Carter Kittrell, Dustin K. James, Bruce E. Brinson, Thomas R. Rybolt, Bruce R. Johnson, Tonya K. Cherukuri, and Paul Cherukuri
ACS Nano, Article ASAP
This paper introduces Teslaphoresis, the directed motion and self-assembly of matter by a Tesla coil, and studies this electrokinetic phenomenon using single-walled carbon nanotubes (CNTs). Conventional directed self-assembly of matter using electric fields has been restricted to small scale structures, but with Teslaphoresis, we exceed this limitation by using the Tesla coil’s antenna to create a gradient high-voltage force field that projects into free space. CNTs placed within the Teslaphoretic (TEP) field polarize and self-assemble into wires that span from the nanoscale to the macroscale, the longest thus far being 15 cm. We show that the TEP field not only directs the self-assembly of long nanotube wires at remote distances (>30 cm) but can also wirelessly power nanotube-based LED circuits. Furthermore, individualized CNTs self-organize to form long parallel arrays with high fidelity alignment to the TEP field. Thus, Teslaphoresis is effective for directed self-assembly from the bottom-up to the macroscale.

Monday, December 21, 2015

New CNT based device from MIT that catches hard to detect molecules

MIT News Reports: Engineers at MIT have devised a new technique for trapping hard-to-detect molecules, using forests of carbon nanotubes. The team modified a simple microfluidic channel with an array of vertically aligned carbon nanotubes — rolled lattices of carbon atoms that resemble tiny tubes of chicken wire. The researchers had previously devised a method for standing carbon nanotubes on their ends, like trees in a forest. With this method, they created a three-dimensional array of permeable carbon nanotubes within a microfluidic device, through which fluid can flow. Now, in a study published this week in the Journal of Microengineering and Nanotechnology, the researchers have given the nanotube array the ability to trap certain particles. To do this, the team coated the array, layer by layer, with polymers of alternating electric charge.

A patterned and cylindrical structure made up of carbon nanotubes. (Courtesy of the researchers, MIT)

A zoomed in view of carbon nanotubes, showing individual tubes. (Courtesy of the researchers, MIT) 

Saturday, October 3, 2015

IBM Research showcases Carbon Nanotubes (CNT) down to 9nm contact

Here is A breakthrough news from IBM Watson Research Center on integrating CNTs down to 9nm contacts. This section from a recent interview with one of the researchers, Shu-Jen Han, behind this work taken from The IBM Research Blog:

Silicon has offered many advantages as a transistor material for the last half century. One biggest perhaps was that it forms a great gate dielectric – SiO2. It also comes with a very pure and high quality substrate, silicon wafers, to start with. And over time we’ve used other materials and device structures to improve its abilities, such as transitioning to high-k metal gate transistors and FinFETs.

On the other hand, for carbonnanotubes, many material issues have to be solved to obtain similar high-quality carbon nanotube wafers for device fabrication. We can’t switch to an entirely new material over night, but silicon is reaching its scaling limits.
Dr. Qing Cao and my other teammates at [the IBM Watson Research Center] developed a way, at the atomic level, to weld - or bond – the metal molybdenum to the carbon nanotubes' ends, forming carbide. Previously, we could only place a metal directly on top of the entire nanotube. The resistance was too great to use the transistor once we reached about 20 nm. But welding the metal at the nanotubes' ends, or end-bonded contacts, is a unique feature for carbon nanotubes due to its 1-D structure, and reduced the resistance down to 9 nm contacts. Key to the breakthrough was shrinking the size of the contacts without increasing electrical resistance, which impedes performance. Until now, decreasing the size of device contacts caused a commensurate drop in performance.

For full details on this breakthrough research please see a recently published article in Science:

End-bonded contacts for carbon nanotube transistors with low, size-independent resistance

Qing Cao, Shu-Jen Han, Jerry Tersoff, Aaron D. Franklin, Yu Zhu, Zhen Zhang, George S. Tulevski, Jianshi Tang, Wilfried Haensch

Science 2 October 2015:
Vol. 350 no. 6256 pp. 68-72
DOI: 10.1126/science.aac8006 

Moving beyond the limits of silicon transistors requires both a high-performance channel and high-quality electrical contacts. Carbon nanotubes provide high-performance channels below 10 nanometers, but as with silicon, the increase in contact resistance with decreasing size becomes a major performance roadblock. We report a single-walled carbon nanotube (SWNT) transistor technology with an end-bonded contact scheme that leads to size-independent contact resistance to overcome the scaling limits of conventional side-bonded or planar contact schemes. A high-performance SWNT transistor was fabricated with a sub–10-nanometer contact length, showing a device resistance below 36 kilohms and on-current above 15 microampere per tube. The p-type end-bonded contact, formed through the reaction of molybdenum with the SWNT to form carbide, also exhibited no Schottky barrier. This strategy promises high-performance SWNT transistors, enabling future ultimately scaled device technologies. 

Saturday, August 15, 2015

Nantero closes additional funding this summer for NRAM and adds ex TSMC Executive to the Board

I have noticed that Carbon Nanotube integration into semiconductor processing as an active device or sensor material has moved into a more mature phase lately. One example is the company Nantero who earlier this summer announced closing a $31.5 million Series E financing round from new and existing investors now adds Previous TSMC Executive Dr. Shang-Yi Chiang to its Advisory Board

According to the press relase Dr. Chiang was previously an Executive Vice President, Co-Chief Operating Officer and Senior Vice President of R&D at TSMC before announcing his retirement in October 2013. 

NRAM is based on forming a film of Carbon Nanotubes (CNT) that are deposited onto a standard silicon substrate that contains an underlying cell select device and array lines (typically transistors or diodes) that interface the NRAM switch. The NRAM acts as a resistive non-volatile random access memory NVRAM and can be placed in two or more resistive modes depending on the resistive state of the CNT fabric. When the CNTs are not in contact the resistance state of the fabric is high and represents a “0” state (see Figure below). When the CNTs are brought into contact, the resistance state of the fabric is low and represents a “1” state. (

“Nantero continues to attract the industry’s brightest and most innovative minds both internally and on an advisory basis,” said Greg Schmergel, Co-Founder, CEO and President of Nantero. “This added expertise will be instrumental in helping the company deliver a new generation of memory with the unique properties of DRAM-like speed, nonvolatility, and ultra-high-densities, for both standalone and embedded use.”

Additional information at the  tells us: NRAM can enable a variety of exciting new features and products in both consumer and enterprise electronics. This new super-fast, ultra-high density memory can replace both DRAM and flash in a single chip, or enable new applications as a storage class memory, while also delivering the low power, high speed, reliability, and endurance needed to drive the next wave of electronics innovation.

  • NRAM Advantages: Extremely Low Power, Super-Fast, High Density, High Endurance
  • Limitless Scalability: Can Scale Below 5 nm to Enable Terabits of Memory in the Future
  • Proven Technology: Successfully Used in Mass Production CMOS Fabs for Many Years
  • Exciting Future Products: Virtual Screens, Next-Generation Enterprise Systems, Rolled-up Tablets, Instant-On Laptops, 3D Video Phones and other products needing huge amounts of fast memory
Here is also a video where the founders of Nantero tells us more about the revolutionary emerging memory technology they are commercializing - claiming scaling down to 5 nm and "unlimited storage capacity" for our future electronic gizmos.

Wednesday, July 30, 2014

MIT present self-assembly of ALD functionalised carbon nanotubes

A team of researchers at MIT has presented a new way to make microstructured surfaces - A method can produce strong, lightweight materials with specific surface properties. by employing ALD coatings. The team has created a new way of manufacturing microstructured surfaces that have novel three-dimensional textures. These surfaces, made by self-assembly of carbon nanotubes, could exhibit a variety of useful properties — including controllable mechanical stiffness and strength, or the ability to repel water in a certain direction.

“We have demonstrated that mechanical forces can be used to direct nanostructures to form complex three-dimensional microstructures, and that we can independently control … the mechanical properties of the microstructures,” says A. John Hart, the Mitsui Career Development Associate Professor of Mechanical Engineering at MIT and senior author of a paper describing the new technique in the journal Nature Communications.

The technique works by inducing carbon nanotubes to bend as they grow. The mechanism is analogous to the bending of a bimetallic strip, used as the control in old thermostats, as it warms: One material expands faster than another bonded to it. But in this new process, the material bends as it is produced by a chemical reaction.
Close-up microscope images of carbon nanotube forms and illustrations of the patterns that produce them. At left, a simple curved form, and at right, complex curved propeller shapes, that can be produced by this carbon nanotube growth method. (MIT News)

The process begins by printing two patterns onto a substrate: One is a catalyst of carbon nanotubes; the second material modifies the growth rate of the nanotubes. By offsetting the two patterns, the researchers showed that the nanotubes bend into predictable shapes as they extend.

“We can specify these simple two-dimensional instructions, and cause the nanotubes to form complex shapes in three dimensions,” says Hart. Where nanotubes growing at different rates are adjacent, “they push and pull on each other,” producing more complex forms, Hart explains. “It’s a new principle of using mechanics to control the growth of a nanostructured material,” he says.

Few high-throughput manufacturing processes can achieve such flexibility in creating three-dimensional structures, Hart says. This technique, he adds, is attractive because it can be used to create large expanses of the structures simultaneously; the shape of each structure can be specified by designing the starting pattern. Hart says the technique could also enable control of other properties, such as electrical and thermal conductivity and chemical reactivity, by attaching various coatings to the carbon nanotubes after they grow.

“If you coat the structures after the growth process, you can exquisitely modify their properties,” says Hart. For example, coating the nanotubes with ceramic, using a method called atomic layer deposition, allows the mechanical properties of the structures to be controlled. “When a thick coating is deposited, we have a surface with exceptional stiffness, strength, and toughness relative to [its] density,” Hart explains. “When a thin coating is deposited, the structures are very flexible and resilient.”

This approach may also enable “high-fidelity replication of the intricate structures found on the skins of certain plants and animals,” Hart says, and could make it possible to mass-produce surfaces with specialized characteristics, such as the water-repellent and adhesive ability of some insects. “We’re interested in controlling these fundamental properties using scalable manufacturing techniques,” Hart says.

Hart says the surfaces have the durability of carbon nanotubes, which could allow them to survive in harsh environments, and could be connected to electronics and function as sensors of mechanical or chemical signals.

Kevin Turner, an associate professor of mechanical engineering and applied mechanics at the University of Pennsylvania who was not involved in this research, says this approach “is quite novel because it allows for the engineering of complex 3-D microstructures [composed] of carbon nanotubes. Traditional microfabrication approaches, such as patterning and etching, generally only allow for the fabrication of simple 3-D structures that are essentially extruded 2-D patterns.”

Turner adds, “A particularly exciting aspect of this work is that the structures are composed of carbon nanotubes, which have desirable mechanical, thermal, and electrical properties.”

Along with Hart, the research team included Michael de Volder of Cambridge University; Sei Jin Park, a visiting doctoral student from the University of Michigan; and Sameh Tawfick, a former postdoc at MIT who is now at the University of Illinois at Urbana-Champaign. The work was supported by the European Research Council, the Defense Advanced Research Projects Agency, and the Air Force Office of Scientific Research.

Monday, May 19, 2014

Improved supercapacitors using ruthenium oxide RGM foam by University of California

As reported today by Sean Nealon, UC Riverside, Researchers at the Univ. of California, Riverside have developed a novel nanometer scale ruthenium oxide anchored nanocarbon graphene foam architecture that improves the performance of supercapacitors, a development that could mean faster acceleration in electric vehicles and longer battery life in portable electronics.

Read the full story here in the R&D Mag or check out the original OPEN ACCESS publication bellow:
Hydrous Ruthenium Oxide Nanoparticles Anchored to Graphene and Carbon Nanotube Hybrid Foam for Supercapacitors
Wei Wang, Shirui Guo, Ilkeun Lee, Kazi Ahmed, Jiebin Zhong, Zachary Favors, Francisco Zaera, Mihrimah Ozkan & Cengiz S. Ozkan          
Scientific Reports 4, Article number: 4452 doi:10.1038/srep04452, 25 March 2014

Abstract: In real life applications, supercapacitors (SCs) often can only be used as part of a hybrid system together with other high energy storage devices due to their relatively lower energy density in comparison to other types of energy storage devices such as batteries and fuel cells. Increasing the energy density of SCs will have a huge impact on the development of future energy storage devices by broadening the area of application for SCs. Here, we report a simple and scalable way of preparing a three-dimensional (3D) sub-5 nm hydrous ruthenium oxide (RuO2) anchored graphene and CNT hybrid foam (RGM) architecture for high-performance supercapacitor electrodes. This RGM architecture demonstrates a novel graphene foam conformally covered with hybrid networks of RuO2 nanoparticles and anchored CNTs. SCs based on RGM show superior gravimetric and per-area capacitive performance (specific capacitance: 502.78 F g−1, areal capacitance: 1.11 F cm−2) which leads to an exceptionally high energy density of 39.28 Wh kg−1 and power density of 128.01 kW kg−1. The electrochemical stability, excellent capacitive performance, and the ease of preparation suggest this RGM system is promising for future energy storage applications.

(a) Schematic illustration of the preparation process of RGM nanostructure foam. SEM images of (b–c) as-grown GM foam (d) Lightly loaded RGM, and (e) heavily loaded RGM. (Source : article above)

Check out the performance in this Ragone plot - Woah - pretty high energy density material!

(a) EIS plots and (b) high frequency region EIS plots of GM, RGM, a control sample (RuO2 nanoparticles only), respectively. (c) Ragone plot related to energy densities and power densities of the packaged whole cell RGM SC, GM SC, RuO2 nanoparticles SC, hydrous ruthenium oxide (RuO2)/graphene sheets composite (GOGSC), RuO2 nanowire/single walled carbon nanotube (SWNT) hybrid film. (Source: articlew above)