IPS gets 100mA from stamp-sized cells

IPS' largest rechargeable, thin-film lithium micro-energy cell is about the size of two postage stamps (50 mm x 25 mm), and some 170 µm thin, but it claims 2.5mAh capacity and continuous current output of 100mA.

Tim Bradow, VP of business development at IPS, says that's enough for a wide range of products. This cell can provide backup power for real time clocks, memory devices, and solid-state drives, and can store the ambient energy collected by solar, piezoelectric, or thermoelectric energy harvesters to power wireless sensors, powered cards, active RFID tags, watches, consumer electronics and medical devices. Bradow also describes products in development that include remote controls that replace infrared diodes with low power RF signals and micro energy cells continuously trickle charged by solar cells, and wireless automotive switches that look to replace the cost and weight of copper wiring with RF signals and micro energy cells continually recharged with vibrational energy harvesting.

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Cymbet makes ‘batteries-in-a-chip’

Cymbet Corp. uses a similar LiPON solid electrolyte, but in an even smaller form factor, for a battery-in-a-chip package that aims to make local energy storage just another electronic component on the board or in the SiP. The chip-scale batteries are finding traction for embedded backup power to replace coin cells or supercapacitors in backing up memory, microcontrollers, and real time clocks in electronic systems.

These chip-like rechargeable lithium-based batteries, with nominal capacity of 50µAh in an 8x8 mm package, are made on silicon wafers with conventional deposition and etch tools, though unconventional materials. The chips withstand up to 260°C, so they can be reflow soldered in normal board assembly. They are sold as a bare die, or packaged with a power management ASIC in a SiP. Cymbet's power management IC converts and regulates input ranging from 2.5V to 5.5V and a steady 3.3V output.

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Consumers Hungry for Connectivity Drive Strong Semiconductor Growth

Innovative new devices in an increasingly mobile and well-networked world will help to drive semiconductor growth in the coming years, although traditional drivers like PCs and cell phones still dominate.

By Aaron Hand

May 27, 2010 – As the semiconductor industry digs out of one of its worst downcycles in its history, there are several driving forces behind predictions for double-digit growth in 2010. But one key factor that's behind not only an expected two-year growth cycle but also a mitigated drop in last year's revenue is continued innovation.

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NEWS FROM THE WORLD OF MATERIALS

Materials in Focus

Redefining electrical current law with the transistor laser 
(University of Illinois)
With the transistor laser, researchers can explore the behavior of photons, electrons and semiconductors. However, harnessing these capabilities hinges on a clear understanding of the physics of the device, and data the transistor laser generated did not fit neatly within established circuit laws governing electrical currents. Kirchhoff's current law states charge input at a node is equal to the charge output. In other words, all the electrical energy going in must go out again. On a basic bipolar transistor, with ports for electrical input and output, the law applies straightforwardly. The transistor laser adds a third port for optical output, emitting light. The unique properties of the transistor laser required researchers of the present study to re-examine and modify the law to account for photon particles as well as electrons, effectively expanding it from a current law to a current-energy law. Simulations based on the modified law accurately fit data collected from the transistor laser. [J. Appl. Phys]

Cleaning AFM probe tip using a grating brush 
(Ultramicroscopy)
Cleaning of atomic force microscope (AFM) tips is crucial for reliable AFM imaging and force measurements. Researchers have now demonstrated that a brush, a calibration grating with supersharp spikes, can be used to mechanically scrub away contaminants by scanning the probe against the spikes at high load at constant-force mode. This allows for removal of organic/inorganic material in a non-destructive and highly efficient manner. In addition, contamination removal and probe study can be completed in a single step. Also, colloidal/particle probes as well as standard AFM tips can be cleaned by thus method. [Ultramicroscopy]

Energy Focus

Nanoholes promise solar power 
(Chemistry World)
Silicon solar cells with arrays of nano-sized holes could outperform their nanowire-based rivals, according to a new study. Nanohole arrays are less fragile and more efficient than nanowires, and can be manufactured using conventional techniques. Nanohole arrays can absorb light even better than nanowire arrays - light that enters the holes will bounce around inside until it is absorbed. In nanowire cells, light is scattered and bounces between nanowires, but the holes seem to do a better job of capturing scattered photons, which increases their energy conversion efficiency. Because the nanohole array is much less fragile than a forest of nanowires, it is also less susceptible to problems associated with broken nanowires, such as recombination of the electrons and positively charged 'holes' that carry current through the device, which boosts the cell's efficiency. [J. Am. Chem. Soc.]

Better platinum catalyst for fuel cells 
(Technology Review)
A new type of catalyst could lead to fuel cells that use a fifth of the platinum they use now. The new material consists of nanoparticles with cores made of a copper-platinum alloy and an outer shell that is mostly platinum. The material is up to five times as efficient as regular platinum. Researchers have revealed the mechanism that makes this catalyst more active than regular platinum. Using x-ray scattering, they discovered that the distance between the platinum atoms that are left on the surface of the nanoparticles is less than the distance in pure platinum nanoparticles. [Nature Chemistry]

Nano Focus

Molecular robots on the rise 
(National Science Foundation)
Recent molecular robotics work has produced so-called DNA walkers, or strings of reprogrammed DNA with 'legs' that enabled them to briefly walk. Now a research team has shown these molecular robotic spiders can in fact move autonomously through a specially-created, two-dimensional landscape. The spiders acted in rudimentary robotic ways, showing they are capable of starting motion, walking for awhile, turning, and stopping. In addition to be incredibly small--about 4 nanometers in diameter--the walkers are also move slowly, covering 100 nanometers in times ranging 30 minutes to a full hour by taking approximately 100 steps. [Nature]

Nanocomposites get in shape 
(Highlights in Chemical Technology)
A material that rapidly heats up and changes shape when connected to a battery has been developed. Researchers blended an electrically conductive network of carbon nanofibers with a shape memory polymer (SMP) - a material that changes from a deformed shape to its original shape induced by a trigger such as a change in temperature. The network of nanofibers enabled the material to heat up very quickly, triggering a change in motion (actuation). [Soft Matter]

Bio Focus

DNA could be backbone of next generation logic chips 
(PhysOrg.com)

In a recent set of experiments, researchers demonstrated that by simply mixing customized snippets of DNA and other molecules, they could create literally billions of identical, tiny, waffle-looking structures. These nanostructures will efficiently self-assemble, and when different light-sensitive molecules are added to the mixture, the waffles exhibit unique and "programmable" properties that can be readily tapped. Using light to excite these molecules, known as chromophores, simple logic gates, or switches, can be created. These nanostructures can then be used as the building blocks for a variety of applications, ranging from the biomedical to the computational. [Small]

Nanotube chip creates bioelectronic link 
(Chemistry World)
A protein coupled with a carbon nanotube has provided a previously unavailable direct biological-to-electronic interface, which its developers hope could lead to brain-controlled prosthetic devices. A group of scientists produced the interface by covering a nanotube in a lipid bilayer that contains ion transporter proteins. The end goal would be to use this kind of system to make a synthetic synaptic junction to transmit signals directly into muscles and tissues. While carbon nanotubes are the right size to integrate with biological molecules, they are usually very hostile to them. Active proteins, like the sodium/potassium ATPase 'biological machine' integrated in the transistor, have therefore not previously been used to control nanoelectronic devices.The scientists came up with the trick of wrapping the nanotube in a lipid bilayer to solve this. [Nano Letters]

Cryo-electron microscope images virus structure with 3.3 Å resolution 
(UCLA)
Researchers report that they have managed to image a virus structure with a resolution of 3.3 angstroms using a cryo-electron microscope. The study demonstrates the great potential of cryo-electron microscopy, or Cryo-EM, for producing extremely high-resolution images of biological samples in their native environment. The work focused on a structural study of the aquareovirus, a non-envelope virus that causes disease in fish and shellfish, in an effort to better understand how non-envelope viruses infect host cells. The group was able to determine that the aquareovirus employs a priming stage to accomplish cell infection. In its dormant state, the virus has a protective protein covering, which it sheds during priming. Once the outer shell has been shed, the virus is in a primed state and is ready to use a protein called an "insertion finger" to infect a cell. [Cell]

Image in Focus

  

ZnO Nanowire Arrays
SEM image of vertically aligned ZnO nanowire arrays with a standing human-like form. Color was added to the original image. Credit: Surawut Chuangchote, Kyoto University
(One of three First Place winners of the Science as Art competition at the 2010 MRS Spring Meeting)

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NEWS FROM THE WORLD OF MATERIALS

Materials in Focus

First images of atomic spin captured 
(Ohio University)
In a new study, researchers present the first images of spin in action. They used a custom-built microscope with an iron-coated tip to manipulate cobalt atoms on a plate of manganese. Through scanning tunneling microscopy, the team repositioned individual cobalt atoms on a surface that changed the direction of the electrons' spin. Images captured showed that the atoms appeared as a single protrusion if the spin direction was upward, and as double protrusions with equal heights when the spin direction was downward. [Nature Nanotechnology]

Sign flips and spin fluctuations in iron high-Tc superconductors 
(Science)
In superconductors, the key process that allows current to travel without resistance is the formation of electron pairs that move as a single quantum state. The mechanism of pairing in the high-temperature (high-Tc) cuprate superconductors is still elusive, so the recent discovery of iron-based superconductors sparked the hope that comparison with the cuprates would lead to a better understanding of pairing in both materials. Researchers now report the experimental determination of the pairing symmetry in FeSe_xTe_1–x. Combined with the recent observation of a spin fluctuation resonance in this material similar to that seen in the cuprates, a compelling hypothesis has emerged that these high-Tc superconductors share a common pairing mechanism. [Science]

Smart sensors use VO₂ grown epitaxially on Si 
(North Carolina State University)
Researchers report vanadium oxide "smart sensors" integrated directly on a silicon chip. This was made possible by growing VO₂ thin films on Si using "domain matching epitaxy". They have explored the mechanisms of how such vanadium oxide sensors work in conjunction with the silicon chips to which they are attached, which yields the ability to improve the reliability of these smart sensors, and account for variable conditions the sensors may be exposed to. Specifically, they report the semiconductor to metal transition (SMT) characteristics of vanadium dioxide grown epitaxially on a Si (001) that is the basis of its sensing properties. [Appl. Phys. Lett.]

Trapped ions detect yoctonewtons force 
(Nature News)
By pushing a cluster of just 60 ions with a tiny electric field, researchers have measured the most minuscule force ever. The result, measuring mere yoctonewtons (10^–24 newtons), beats previous record lows by several orders of magnitude. Previously, researchers were able to successfully measure around an attonewton (10^–18 N) of force by giving small pushes to microscopic paddles or wires and then watching them vibrate. These systems work well, but are limited by factors such as their relatively large size. The new technique eschews the paddle-type systems in favor of just 60 beryllium-9 ions. [Arxiv]

Energy Focus

Fuel cell runs on water and air 
(Highlights in Chemical Technology)
A fuel cell that produces power using only water and a warm breeze has been developed by researchers.In the new cell, water is oxidized catalytically to molecular oxygen, protons and electrons at the anode, while the reverse reaction takes place at the cathode. As in normal fuel cells, the cathode and anode are separated by a polymer electrolyte membrane which allows the protons to cross to the cathode while the electrons are forced to make their way through a wire, creating a current. The water that forms at the cathode is evaporated by the air flow, keeping the water concentration gradient between the two electrodes, which acts as the driving force for the reaction. Unlike other fuel cells no change in enthalpy occurs as water reacts to form water. This means that typically minor contributions, such as changes in entropy, become key factors in the energy output. [Energy Environ. Sci.]

Nano Focus

Seeing Moiré in graphene 
(PhysOrg.com)
Researchers have demonstrated that atomic scale moiré patterns can be used to measure how sheets of graphene are stacked and reveal areas of strain. They created graphene on the surface of a silicon carbide substrate by heating one side so that only carbon, in the form of multilayer sheets of graphene, was left. Using a custom-built scanning tunneling microscope, they were able to peer through the topmost layers of graphene to the layers beneath. This process, which the group dubbed atomic moir interferometry, enabled them to image the patterns created by the stacked graphene layers, which in turn allowed the group to model how the hexagonal lattices of the individual graphene layers were stacked in relation to one another. [Physical Review B]

Measuring wettability with sub-nanometer resolution 
(Massachusetts Institute of Technology)
Wettability is crucial to a wide variety of processes. Until now, the only way to quantify this important characteristic of a material's surface has been to measure the shapes of the droplets that form on it, and this method has very limited resolution. But a team of researchers has found a way to obtain images using atomic force microscopy (AFM) that improves the resolution of such measurements by a factor of 10,000 or more, allowing for unprecedented precision in determining the details of the interactions between liquids and solid surfaces. In addition, the new method can be used to study curved, textured or complex solid surfaces, something that could not be done previously. [Nature Nanotechnology]

Nanosculptors could help focus light on silicon chips 
(New Scientist)

Credit: IBM

Researchers have sculpted a 1:180 billion scale model of the Matterhorn, the 4478-metre-tall Alpine peak on the Swiss-Italian border. The team carved the minute mountain using a technique they have developed for making high-density computer storage. They found they could evaporate material from a surface by heating a punching needle to 330 °C and using it as a kind of chisel. They carved their microscopic Matterhorn from a glassy organic material whose molecules are held together by hydrogen bonds, forces of attraction between partially positive hydrogen ions in one molecule and electron-rich oxygen ions in another. [Science]

Atomic force microscopy of cells using a nanowire cantilever 
(Lawrence Berkeley National Lab)
The core of AFM imaging is a cantilever with a sharp tip that deflects as it encounters undulations across a surface. Due to a minimum force required for imaging, conventional AFM cantilevers can deform or even tear apart living cells and other biological materials. Scientists have now developed nanowire cantilevers whose gentle touch could help discern the workings of living cells and other soft materials in their natural, liquid environment. Used in combination with a new detection mechanism, this new imaging tool is sensitive enough to investigate soft materials without the limitations present in other cantilevers. [Phys. Rev. Lett.]

Bio Focus

Nanoparticles protect bone marrow during radiation cancer therapy 
(Albert Einstein College of Medicine of Yeshiva University)
Melanin-covered nanoparticles could protect bone marrow from the harmful effects of radiation therapy. Radiation therapy is used to kill cancer cells and shrink tumors. But because radiation also damages normal cells, doctors must limit the dose. Melanin, the naturally occurring pigment that gives skin and hair its color, helps shield the skin from the damaging effects of sunlight and has been shown to protect against radiation. Researchers created "melanin nanoparticles" by coating 20 nanometers diameter silica particles with several layers of melanin pigment that they synthesized in their laboratory. The researchers found that these particles successfully lodged in bone marrow after being injected into mice. Then, in a series of experiments, they investigated whether their nanoparticles would protect the bone marrow of mice treated with two types of radiation. [International Journal of Radiation Oncology*Biology*Physics]

Image in Focus 

  

Nano PacMan made of copper oxide
Scanning electron microscope image of a copper oxide cluster, 3.5 microns in diameter, prepared by evaporation and condensation over an alumina substrate. The smiley nose and eye are present in the original SEM image, which has only been color-enhanced.
Credit: Elisabetta Comini, University of Brescia, Italy

(One of three First Place winners of the Science as Art competition at the 2010 MRS Spring Meeting)

[We invite you to submit your images to the Editor for possible inclusion in this feature]

Industry Focus

Process Advances to Accelerate 3D Manufacturing Readiness Reported at MRS Spring Meeting
With a focus on providing cost-effective and reliable solutions to speed manufacturing readiness of 3D technology options, experts from SEMATECH's 3D interconnect program based at the College of Nanoscale Science and Engineering's (CNSE) Albany NanoTech Complex outlined new developments in wafer bonding, copper removal, and wafer thinning at the 2010 Materials Research Society (MRS) Spring Meeting on April 5-9 in San Francisco, CA. 3D integration offers the promise of higher performance, higher density, higher functionality, smaller form factor, and potential cost reduction. In this emerging field, new and improved technologies and integration schemes will be necessary to realize 3D's potential as a manufacturable and affordable path to sustaining semiconductor productivity growth. At the MRS Meeting, SEMATECH researchers described several practical 3D integration achievements – applicable across various 3D processes – in areas such as high-aspect ratio TSVs, wafer bonding, and thinning of interconnect test structures.

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