Category Archives: Process Materials

Physicists at the University of Warwick have today, Thursday 19th April 2018, published new research in the fournal Science today 19th April 2018 (via the Journal’s First Release pages) that could literally squeeze more power out of solar cells by physically deforming each of the crystals in the semiconductors used by photovoltaic cells.

This is an artists impression of squeezing more power out of solar cells by physically deforming each of the crystals in the semiconductors used by photovoltaic cells. Credit: University of Warwick/Mark Garlick

This is an artists impression of squeezing more power out of solar cells by physically deforming each of the crystals in the semiconductors used by photovoltaic cells. Credit: University of Warwick/Mark Garlick

The paper entitled the “Flexo-Photovoltaic Effect” was written by Professor Marin Alexe, Ming-Min Yang, and Dong Jik Kim who are all based in the University of Warwick’s Department of Physics.

The Warwick researchers looked at the physical constraints on the current design of most commercial solar cells which place an absolute limit on their efficiency. Most commercial solar cells are formed of two layers creating at their boundary a junction between two kinds of semiconductors, p-type with positive charge carriers (holes which can be filled by electrons) and n-type with negative charge carriers (electrons).

When light is absorbed, the junction of the two semiconductors sustains an internal field splitting the photo-excited carriers in opposite directions, generating a current and voltage across the junction. Without such junctions the energy cannot be harvested and the photo-exited carriers will simply quickly recombine eliminating any electrical charge.

That junction between the two semiconductors is fundamental to getting power out of such a solar cell but it comes with an efficiency limit. This Shockley-Queisser Limit means that of all the power contained in sunlight falling on an ideal solar cell in ideal conditions only a maximum of 33.7% can ever be turned into electricity.

There is however another way that some materials can collect charges produced by the photons of the sun or from elsewhere. The bulk photovoltaic effect occurs in certain semiconductors and insulators where their lack of perfect symmetry around their central point (their non-centrosymmetric structure) allows generation of voltage that can be actually larger than the band gap of that material (the band gap being the gap between the valence band highest range of electron energies in which electrons are normally present at absolute zero temperature and the conduction band where electricity can flow).

Unfortunately the materials that are known to exhibit the anomalous photovoltaic effect have very low power generation efficiencies, and are never used in practical power-generation systems.

The Warwick team wondered if it was possible to take the semiconductors that are effective in commercial solar cells and manipulate or push them in some way so that they too could be forced into a non-centrosymmetric structure and possibly therefore also benefit from the bulk photovoltaic effect.

For this paper they decided to try literally pushing such semiconductors into shape using conductive tips from atomic force microscopy devices to a “nano-indenter” which they then used to squeeze and deform individual crystals of Strontium Titanate (SrTiO3), Titanium Dioxide (TiO2), and Silicon (Si).

They found that all three could be deformed in this way to also give them a non-centrosymmetric structure and that they were indeed then able to give the bulk photovoltaic effect.

Professor Marin Alexe from the University of Warwick said:

“Extending the range of materials that can benefit from the bulk photovoltaic effect has several advantages: it is not necessary to form any kind of junction; any semiconductor with better light absorption can be selected for solar cells, and finally, the ultimate thermodynamic limit of the power conversion efficiency, so-called Shockley-Queisser Limit, can be overcome. There are engineering challenges but it should be possible to create solar cells where a field of simple glass based tips (a hundred million per cm2) could be held in tension to sufficiently de-form each semiconductor crystal. If such future engineering could add even a single percentage point of efficiency it would be of immense commercial value to solar cell manufacturers and power suppliers.”

Collaborative research team of Prof. Jun Takeda and Associate Prof. Ikufumi Katayama in the laboratory of Yokohama National University (YNU) and Nippon Telegraph and Telephone (NTT) successfully observed petahertz (PHz: 1015of a hertz) electron oscillation. The periodic electron oscillations of 667-383 attoseconds (as: 10-18 of a second) is the fastest that has ever been measured in the direct time-dependent spectroscopy in solid-state material.

NIR femtosecond pulse (pump pulse) induces the electron oscillation, which is monitored by the extreme ultraviolet IAP (probe pulse) based on the transient absorption spectroscopy. Credit: Nippon Telegraph and Telephone (NTT)

NIR femtosecond pulse (pump pulse) induces the electron oscillation, which is monitored by the extreme ultraviolet IAP (probe pulse) based on the transient absorption spectroscopy. Credit: Nippon Telegraph and Telephone (NTT)

As high-speed shutter cameras capture motions of fast-moving objects, researchers generally use laser (pulse) like instantaneous strobe light in order to observe the ultrafast motion of an electron underlying a physical phenomenon. The shorter the pulse duration, the faster the electron oscillation can be observed. The frequency of the lightwave-field in the visible and ultraviolet region can reach the petahertz (PHz: 1015 of a hertz), which means that the oscillation periodicity can achieve attosecond (as: 10-18 of a second) duration.

In previous studies, NTT researchers of the team generated an isolated attosecond pulse (IAP) [H. Mashiko et al., Nature commun. 5, 5599 (2014)] and monitored the electron oscillation with 1.2-PHz frequency using gallium-nitride (GaN) semiconductor [H. Mashiko et al., Nature Phys. 5, 741 (2016)]. The next challenges are the observation of faster electron oscillation in the chromium doped sapphire (Cr:Al2O3) insulator and the characterization of the ultrafast electron dephasing.

The paper, published in the journal Nature communications reports a successful observation of the near-infrared (NIR) pulse-induced multiple electronic dipole oscillations (periodicities of 667-383 as) in the Cr:Al2O3 solid-state material. The measurement is realized by the extreme short IAP (192-as duration) and the use of stable pump (NIR pulse) and probe (IAP) system (timing jitter of ~23 as). The characterized electron oscillations are the fastest that has ever been measured in the direct time-dependent spectroscopy. In addition, the individual dephasing times in the Cr donor-like intermediate level and the Al2O3 CB state are revealed.

Dr. Hiroki Mashiko, a NTT scientist of the team, said, “We contrived the robust pump-probe system with an extremely short isolated attosecond pulse, which led to the observation of the fastest electron oscillation in solid-state material in recorded history. The benefits of this study are directly related to the control of various optical phenomena through the dielectric polarization, and the results will help the development of future electronic and photonic devices.”

Over the past decades, computers have become faster and faster and hard disks and storage chips have reached enormous capacities. But this trend cannot continue forever: we are already running up against physical limits that will prevent silicon-based computer technology from attaining any impressive speed gains from this point on. Researchers are particularly optimistic that the next era of technological advancements will start with the development of novel information-processing materials and technologies that combine electrical circuits with optical ones. Using short laser pulses, a research team led by Misha Ivanov of the Max Born Institute in Berlin together with scientists from the Russian Quantum Center in Moscow have now shed light on the extremely rapid processes taking place within these novel materials. Their results have appeared in the prestigious journal Nature Photonics.

Of particular interest for modern material research in solid state physics are “strongly correlated systems”, so called for the strong interactions between the electrons in these materials. Magnets are a good example of this: the electrons in magnets align themselves in a preferred direction of spin inside the material, and it is this that produces the magnetic field. But there are other, entirely different structural orders that deserve attention. In so-called Mott insulators for example, a class of materials now being intensively researched, the electrons ought to flow freely and the materials should therefore be able to conduct electricity as well as metals. But the mutual interaction between electrons in these strongly correlated materials impedes their flow and so the materials behave as insulators instead.

By disrupting this order with a strong laser pulse, the physical properties can be made to change dramatically. This can be likened to a phase transition from solid to liquid: as ice melts, for example, rigid ice crystals transform into free-flowing water molecules. Very similarly, the electrons in a strongly correlated material become free to flow when an external laser pulse forces a phase transition in their structural order. Such phase transitions should allow us to develop entirely new switching elements for next-generation electronics that are faster and potentially more energy efficient than present-day transistors. In theory, computers could be made around a thousand times faster by “turbo-charging” their electrical components with light pulses.

The problem with studying these phase transitions is that they are extremely fast and it is therefore very difficult to “catch them in the act”. So far, scientists have had to content themselves with characterising the state of a material before and after a phase transition of this kind. Researchers Rui E. F. Silva, Olga Smirnova, and Misha Ivanov of the Berlin Max Born Institute, however, have now devised a method that will, in the truest sense, shed light on the process. Their theory involves firing extremely short, tailored laser pulses at a material – pulses that can only recently be produced in the appropriate quality given the latest developments in lasers. One then observes the material’s reaction to these pulses to see how the electrons in the material are excited into motion and, like a bell, emit resonant vibrations at specific frequencies, as harmonics of the incident light.

“By analysing this high harmonic spectrum, we can observe the change in the structural order in these strongly correlated materials ‘live’ for the first time,” says first author of the paper Rui Silva of the Max Born Institute. Laser sources capable of targetedly triggering these transitions have only been available since very recently. The laser pulses namely have to be amply strong and extremely short – on the order of femtoseconds in duration (millionths of a billionth of a second).

In some cases, it takes only a single oscillation of light to disrupt the electronic order of a material and turn an insulator into a metal-like conductor. The scientists at the Berlin Max Born Institute are among the world’s leading experts in the field of ultrashort laser pulses.

“If we want to use light to control the properties of electrons in a material, then we need to know exactly how the electrons will react to light pulses,” Ivanov explains. With the latest-generation laser sources, which allow full control over the electromagnetic field even down to a single oscillation, the newly published method will allow deep insights into the materials of the future.

Researchers from Tomsk Polytechnic University together with their international colleagues have discovered a method to modify and use the one-atom thin conductor of current and heat, graphene without destroying it. Thanks to the novel method, the researchers were able to synthesize on single-layer graphene a well-structured polymer with a strong covalent bond, which they called ‘polymer carpets’. The entire structure is highly stable; it is less prone to degradation over time that makes the study promising for the development of flexible organic electronics. Also, if a layer of molybdenum disulfide is added over the ‘nanocarpet’, the resulting structure generates current under exposure to light. The study results were published in Journal of Materials Chemistry C.

This is the scheme for obtaining a hybrid structure of 'graphene-polymer'. Credit: Tomsk Polytechnic University

This is the scheme for obtaining a hybrid structure of ‘graphene-polymer’. Credit: Tomsk Polytechnic University

Graphene is simultaneously the most durable, light and an electrically conductive carbon material. It can be used for manufacturing solar batteries, smartphone screens, thin and flexible electronics, and even in water filters since graphene films pass water molecules and stop all other compounds. Graphene should be integrated into complex structures to be used successfully. However, it is a challenge to do that. According to scientists, graphene itself is stable enough and reacts poorly with other compounds. In order to make it react with other elements, i.e. to modify it, graphene is usually at least partially destroyed. This modification degrades the properties of the materials obtained.

Professor Raul D. Rodriguez from the Research School for Chemistry & Applied Biomedical Sciences says: ‘When functionalizing graphene, you should be very careful. If you overdo it, the unique properties of graphene are lost. Therefore, we decided to follow a different path.

In graphene, there are inevitable nanodefects, for example, at the edges of graphene and wrinkles in the plane. Hydrogen atoms are often attached to such defects. It is this hydrogen that can interact with other chemicals.’

To modify graphene, the authors use a thin metal substrate on which a graphene single-layer is placed. Then graphene is covered with a solution of bromine-polystyrene molecules. The molecules interact with hydrogen and are attached to the existing defects, resulting in polyhexylthiophene (P3HT). Further exposed to light during the photocatalysis, a polymer begins to ‘grow’.

‘In the result, we obtained the samples which structure resembles ‘polymer carpets’ as we call them in the paper. Above such a ‘polymer carpet’ we place molybdenum disulfide. Due to a unique combination of materials, we obtain a ‘sandwich’ structure’ that functions like a solar battery. That is, it generates current when exposed to light. In our experiments a strong covalent bond is established between the molecules of the polymer and graphene, that is critical for the stability of the material obtained,’ notes Rodriguez.

According to the researcher, the method for graphene modification, on the one hand, enables obtaining a very sturdy compound; on the other hand, it is rather simple and cheap as affordable materials are used. The method is versatile because it makes growing very different polymers directly on graphene possible.

‘The strength of the obtained hybrid material is achieved additionally because we do not destroy graphene itself but use pre-existing defects, and a strong covalent bond to polymer molecules. This allows us to consider the study as promising for the development of thin and flexible electronics when solar batteries can be attached to clothes, and when deformed they will not break,’ the professor explains.

NUST MISIS scientists have finally found out why a material that could potentially become the basis for ultra-fast memory in new computers is formed. Professor Petr Karpov and Serguei Brazovskii, both researchers at NUST MISIS, have managed to develop a theory which explains the mechanism of the latent state formation in layered tantalum disulfide, one of the most promising materials for modern microelectronics. The latent state of matter (which will be discussed further) was discovered by Serguei Brazovskii with a group of experimenters from Slovenia in 2014. The experiment that led to the beginning of the “boom” for the studies of layered materials lied in the fact that the tantalum disulfide sample, which was less than 100 nanometers big, was affected by an ultrashort laser (an electric pulse). The state of the material changed because of pulses in the irradiated area, and the sample became either a conductor of dielectrics or vice versa, depending on the experimenters’ wish. The switching even occurred in just one picosecond –a far quicker rate than in the “fastest” materials used as storage mediums in modern computers. That condition didn’t fade after exposure, but instead persisted. Accordingly, the material has become a potential candidate for the basis of the next generation of information data mediums.

Serguei Brazovskii is currently serving as the leading scientist of the “Theory of locally adjustable electronic states in layered materials” project at NUST MISIS, as well as working as a leading scientist at the University of Paris-Sud (Orsay, France) Laboratory of Theoretical Physics and Statistical Models.

Professor Petr Karpov, engineer at the NUST MISIS Department for Theoretical Physics and Quantum Technologies, explained the root of the matter, “The ‘boom’ in the study of layered tantalum disulfide happened, as well as a number of articles on this topic in different journals being published, after our colleagues from Slovenia discovered the latent state of the matter, unattainable in conventional (thermodynamic) phase transitions. However, most of these works were experimental, and the theory lagged behind. That is, the state could have been received but why did it turn out [that way]? What were the mechanisms of its formation? What its nature is in general, remained unclear. Why doesn’t the system return to its original state, continuing to remain in modified form indefinitely? In this article we tried to find the theoretical justification of the occurring processes”.

Tantalum disulfide belongs to a special group of conductor materials in which so-called charge-density waves are formed. This means that in addition to the natural peaks of electron density caused by the presence of an atom, there is also another periodicity that is several times greater than the distance between the adjacent atoms of the crystal lattice. In this case, the degree of that periodicity is the “root of thirteen”, so there is quite a large difference.

Picture A shows a layer of tantalum atoms. The period between the “superpeaks” is marked with a red arrow. The state of the different sites in the tantalum disulfide layer differ from each other in the fact that the maximum electron density is centered on tantalum atoms. The red ones show one state, while the “blue” and “white” ones show other states.

The work of NUST MISIS scientists consisted of constructing and studying a universal theoretical model that could describe the most important and intriguing property of the newly discovered state: the formation and transformation of nano-structural mosaics (pic. b). Some of the metal atoms fly out of the lattice after the processing of electrical impulses in the sample of layered tantalum disulfide, and that causes defects — charged vacancies in the electronic crystal.

However, instead of keeping a maximum distance from each other, the charges are “smeared” along the linear chains of tantalum atoms, forming boundaries of zones with different states of tantalum atoms. These “domains” then essentially chain up, connected to a global network. Manipulating these nanosets is the reason for the switching and memory effects observed in the material.

“We tried to find out why similar charges in such a structure do not repel, but, in fact, are attracted to each other. It turned out that this process is energetically more profitable than the maximum removal of positive charges from each other because the formation of fractional charged domain walls minimizes the charge of the constituent wall of atoms, which is why the domain system becomes more stable. This is completely confirmed by the experiment, and the whole crystal can be taken to such a state with a domain mosaic and globules dividing the walls”, — added Petr Karpov.

According to the scientists, thanks to the development of this theory, it is possible to confirm that the domain state of tantalum disulfide can be used for long-term storage and super-fast operation of information.

Cree, Inc. (NASDAQ: CREE) announces that it signed a non-exclusive, worldwide, royalty-bearing patent license agreement with Nexperia BV, a Dutch company. The agreement provides Nexperia access to Cree’s extensive gallium nitride (GaN) power device patent portfolio, which includes over 300 issued U.S. and foreign patents that describe inventive aspects of high electron mobility transistor (HEMT) and GaN Schottky diode devices. The portfolio addresses novel device structures, materials and processing improvements, and packaging technology. The patent license involves no transfer of technology.

“Cree was founded to develop novel compound semiconductor materials like GaN and SiC and to create devices that capitalize on their unique properties,” said John Palmour, Cree co-founder and CTO of Wolfspeed, a Cree company. “Cree’s decades of innovation are now yielding devices that enable market introductions of new power management and wireless systems. To help facilitate the growth of these new markets, Cree is licensing its GaN power device patents for GaN power-management systems.”

Graphene, a two-dimensional lattice of carbon atoms, has attracted enormous interest from a broad base of the research community for more than one decade. Graphene nanoribbons (GNRs), narrow strips of graphene, being quasi one-dimensional, possess complementary features relative to their two-dimensional counterpart of graphene sheets. Based on theoretical calculations, GNRs’ electrical properties can be controlled by the width and edge configuration and they can vary from being metallic to semiconducting. The physical properties of the GNRs depend significantly on the size and number of layers, which in turn depend on their synthesis method. There are three major approaches for synthesis of GNRs: cutting graphene by different lithographic techniques; bottom-up synthesis from polycyclic molecules; and unzipping of carbon nanotubes (CNTs). While the bottom-up method provides a route to precise edge control, and the lithographic method can afford GNRs with precise placement, the unzipping method has the advantage of mass-production on a large scale.

MWCNT unzipping methods can be classified into four major types: the reductive-intercalation-assisted approach, the oxidative unzipping, the electrochemical unzipping, and the group of methods that can be denoted as miscellaneous. The first approach is based on the well-known ability of alkali metals to intercalate graphite with expansion in the Z-axis direction. Being applied toward MWCNTs, such lattice expansion induces extreme stress within the concentric walls, resulted in the bursting, or longitudinal opening, of the tubes. The resulted GNRs are highly conductive, but they remain multi-layered and foliated. Due to the attraction between the surfaces, they do not exfoliate to single-layer ribbons.

The oxidative approach involves treatment of MWCNTs in acidic oxidative media with the formulation almost identical to that used in production of graphene oxide (GO) from graphite by the Hummers method. The resulting product is graphene oxide nanoribbons (GONRs). Unlike GNRs obtained by the reductive-intercalation method, GONRs easily exfoliate in aqueous solution, and they can be obtained as single-layered structures. A reaction mechanism for oxidative unzipping was proposed by Kosynkin et al.1 Invoking the classical oxidation of the alkenes by permanganate in acids, the first step is the formation of manganate ester on a C-C bond, and the second step is the rupture of the C-C bond with formation of ketones at the newly formed edges. This mechanism was further developed in the theoretical work by Rangel et al.2 The original synthesis spawned numerous studies on oxidative unzipping of MWCNTs. In many reports, the unzipping process was denoted as “chemical” as opposed to the “intercalation-exfoliation”, indicating that the permanganate-induced oxidative mechanism has been commonly accepted, and was even suggested toward unzipping SWCNTs.

The newly proposed mechanism was based on the Lab’s competences on the studies of the mechanism of GO formation of graphite that involves three consecutive steps: (a) intercalation of graphite by sulfuric acid with formation of a stage-1 H2SO4-graphite intercalation compound (GIC); (b) conversion of stage-1 H2SO4-GIC into pristine GO, and (c) exfoliation of GO to single-layer sheets upon exposure to water. Thus, under given conditions, formation of stage-1 H2SO4-GIC is unavoidable for any graphitic material. Subsequently, the mechanism of the oxidative unzipping of MWCNTs might be also intercalation-driven. If this is correct, one should be able to stop the reaction after the first intercalation-unzipping step before the second oxidation step proceeds. If attained, this will afford unzipped but not oxidized or minimally oxidized products possessing properties similar to reductively unzipped GNRs obtained by potassium or sodium-potassium metal intercalation. In this work, the Lab investigated the impact of the two key parameters, the KMnO4/MWCNT ratio, and the time of reaction on the structure and composition of as-obtained GNR products, and derived a revised and more complete understanding of the unzipping process.

The researchers demonstrated that the mechanism of the oxidative unzipping of MWCNTs is indeed intercalation-driven. The overall unzipping process involves the same three steps as in the course of GO production from graphite by the Hummers and modified Hummers methods: intercalation, oxidation, and exfoliation. With MWCNTs, the intercalation is associated with simultaneous unzipping. At low KMnO4/MWCNT ratios, one can obtain GNRs with characteristics similar to those produced by reductive unzipping. 0.12 wt equiv KMnO4 is the threshold ratio sufficient for almost complete unzipping, with only small amounts of covalent oxidation. Controlling the KMnO4/MWCNT ratio and time of reaction allows one to produce GNRs with the properties varying in a broad continuous range from multi-layered graphenic GNRs through single-layered GONRs. Thus, the team answered several questions that remained open in the field of unzipping MWCNTs, such as the reason why the inner-most walls of the nanotubes remain zipped. The intercalation-driven reaction mechanism provides a rationale for the impossibility of unzipping single-wall and few-wall CNTs, and aids in a reevaluation of the data from the oxidative unzipping process.

Indium Corporation, one of more than 3,000 ON Semiconductor production suppliers, was selected for its commitment to ensuring high quality and supply continuity in an evolving semiconductor market.

The annual Perfect Quality Award was presented to Weng Fai Pang, Managing Director for Asia-Pacific Operations, and Tim Twining, Vice President of Marketing, at ON Semiconductor’s Supplier Executive Conference in March in Hong Kong, China.

Indium Corporation is a materials manufacturer and supplier to the global electronics, semiconductor, thin-film, and thermal management markets. Products include solders and fluxes; brazes; thermal interface materials; sputtering targets; indium, gallium, germanium, and tin metals and inorganic compounds; and NanoFoil®. Founded in 1934, the company has global technical support and factories located in China, Malaysia, Singapore, South Korea, the United Kingdom, and the USA.

When power generators like windmills and solar panels transfer electricity to homes, businesses and the power grid, they lose almost 10 percent of the generated power. To address this problem, scientists are researching new diamond semiconductor circuits to make power conversion systems more efficient.

The view of the H-diamond MOSFET NOR logic circuit from above (left), and the operation of the NOR logic circuits, showing that the circuit only produces voltage when both inputs are at zero. Credit: Liu et al.

The view of the H-diamond MOSFET NOR logic circuit from above (left), and the operation of the NOR logic circuits, showing that the circuit only produces voltage when both inputs are at zero. Credit: Liu et al.

A team of researchers from Japan successfully fabricated a key circuit in power conversion systems using hydrogenated diamond (H-diamond.) Furthermore, they demonstrated that it functions at temperatures as high as 300 degrees Celsius. These circuits can be used in diamond-based electronic devices that are smaller, lighter and more efficient than silicon-based devices. The researchers report their findings this week in Applied Physics Letters, from AIP Publishing.

Silicon’s material properties make it a poor choice for circuits in high-power, high-temperature and high-frequency electronic devices. “For the high-power generators, diamond is more suitable for fabricating power conversion systems with a small size and low power loss,” said Jiangwei Liu, a researcher at Japan’s National Institute for Materials Science and a co-author on the paper.

In the current study, researchers tested an H-diamond NOR logic circuit’s stability at high temperatures. This type of circuit, used in computers, gives an output only when both inputs are zero. The circuit consisted of two metal-oxide-semiconductor field-effect transistors (MOSFETs), which are used in many electronic devices, and in digital integrated circuits, like microprocessors. In 2013, Liu and his colleagues were the first to report fabricating an E-mode H-diamond MOSFET.

When the researchers heated the circuit to 300 degrees Celsius, it functioned correctly, but failed at 400 degrees. They suspect that the higher temperature caused the MOSFETs to breakdown. Higher temperatures may be achievable however, as another group reported successful operation of a similar H-diamond MOSFET at 400 degrees Celsius. For comparison, the maximum operation temperature for silicon-based electronic devices is about 150 degrees.

In the future, the researchers plan to improve the circuit’s stability at high temperatures by altering the oxide insulators and modifying the fabrication process. They hope to construct H-diamond MOSFET logic circuits that can operate above 500 degrees Celsius and at 2.0 kilovolts.

“Diamond is one of the candidate semiconductor materials for next-generation electronics, specifically for improving energy savings,” said Yasuo Koide, a director at the National Institute for Materials Science and co-author on the paper. “Of course, in order to achieve industrialization, it is essential to develop inch-sized single-crystal diamond wafers and other diamond-based integrated circuits.”

Veeco Instruments Inc. (Nasdaq: VECO) today announced that ON Semiconductor (Nasdaq: ON) has ordered its Propel® High-volume Manufacturing (HVM) Gallium Nitride (GaN) Metal Organic Chemical Vapor Deposition (MOCVD) system. Based on its successful beta evaluation of the Propel HVM tool, ON Semiconductor ordered the production-level Propel system for GaN power electronics manufacturing. As the industry’s first single-wafer cluster platform, the Propel GaN MOCVD system is specifically designed for high-voltage power-management devices used in data centers; automotive, information and communication technology; defense; aerospace and power distribution systems, among other applications.

“Our prior learning with Veeco’s K465i™ GaN MOCVD system drove us to investigate the Propel HVM platform for our production ramp,” said Marnix Tack, PhD, senior director of corporate R&D and Open Innovation at ON Semiconductor. “The beta test results demonstrated superior device performance with high uniformity and within-wafer and wafer-to-wafer repeatability, while meeting our cost-of-ownership targets for six- and eight-inch wafers. As such, the Propel HVM system proved to be the most suitable platform for our power electronics manufacturing needs.”

The Propel HVM platform is based on Veeco’s innovative single-wafer system with proprietary IsoFlange™ and SymmHeat™ technologies that provide homogeneous laminar flow and uniform temperature profile across the entire wafer. The system enables production of power electronics, laser diodes, RF devices and advanced LEDs with higher performance and production yields while ensuring very low cost-of-ownership.

“The Propel HVM platform is rapidly gaining traction in the industry as innovative companies like ON Semiconductor recognize the benefits of GaN-on-silicon, which will partially replace current silicon technology for power electronics,” commented Peo Hansson, PhD, senior vice president and general manager of Veeco MOCVD operations. “With its highly controlled doping, run-to-run stability, superior wafer uniformity, high productivity and uptime, Propel HVM extends the benefits of our TurboDisc® platform to a unique single-wafer architecture. These capabilities benefit customers that seek a superior solution for manufacturing while providing a path for scaling to eight-inch wafers and expansion to RF and other advanced applications.”

GaN is a wide band gap semiconductor material with specific advantages over conventional technologies such as gallium arsenide (GaAs) and silicon carbide (SiC). GaN has enormous potential in the short term due to its benefits in terms of thermal behavior, efficiency, weight and size. According to market research firm Yole Développement, the GaN power device business was worth $14 million in 2016, and projects that it will reach $460 million by 2022, with a compound annual growth rate (CAGR) of 79 percent. GaN-based devices will be used increasingly in RF amplifiers, LEDs and high voltage applications among others, primarily due to their abilities to operate at high frequency, power density and temperature with improved efficiency and linearity.

Veeco is discussing the power of its innovative MOCVD and wet etch systems in the “5G: Where Are We and What’s Next?” track at the CS International Conference this week in Brussels, Belgium. Somit Joshi, senior director of MOCVD marketing is presenting a session titled, “Enabling GaN RF and Power Electronics through Innovative MOCVD and Wet Etch Process Technologies,” on Wednesday, April 11, and the Veeco team will also be accepting the CS Industry 2018 Award for Innovation for its GENxcel™ R&D MBE System at the awards ceremony held during the conference.