Category Archives: Packaging Materials

Advanced Semiconductor Engineering, Inc (TAIEX: 2311, NYSE: ASX), a semiconductor assembly and test service provider, announced that its K7 manufacturing facility in Kaohsiung has received the Green Factory Label from the Industrial Development Bureau, Ministry of Economic Affairs, Taiwan. K7 is the sixth factory following K3, K5, K11, K12 and K15, at the ASE Kaohsiung Nantze campus to receive the label.

ASE is fully committed to corporate sustainability through actions that produce tangible results and meet our goal of co-existence with the environment. In 2009, ASE Kaohsiung green building plans were drawn up to combine nature with technology, and provide a green factory environment optimized for living, productivity and the ecology. The ASE K7 building has incorporated green innovation, eco-friendly designs, energy and water conservation, waste reduction, low carbon and various environmental benchmarks to achieve the green factory label.

‘Sustainability has always been at the core of ASE’s corporate philosophy,’ said KC Chou, senior vice president, ASE. ‘In 2014, ASE Kaohsiung implemented the EEWH-RN system and adopted ‘clean production’. Beginning with sustainable product design and production, green management, social responsibility to innovation; these four facets helped reduce resource consumption, reduce waste, lower impacts to the environment and other improvements that aim to strike a balance between economic and environmental sustainability. Our Kaohsiung facilities are constantly challenged to establish energy reduction goals and each department regularly proposes diverse programs to lower carbon footprints. This year, K7 is also working towards achieving the EEWH-RN diamond grade. At ASE, we will continuously raise the bar on our sustainability performance,’ he concluded.

About ASE Sustainability Actions and Results

ASE K7

  • Green innovation. The use of DI water to replace acetic acid reduced the usage of organic acid by 14,400 liters.
  • Green material usage. The use of boron-free developing agent reduced boron-containing agent usage by 1,830 liters and boron-containing liquid waste by 2,015 metric tons per year. The use of lead-free solder paste reduced usage of lead paste by 1,500 kg per year.
  • Energy efficient manufacturing process. Improvements made to the adsorption dryer reduced energy usage by 278,495 kWh per year.
  • Water efficiency. The use of chamber piping to control water flow resulted in water savings of 314.52 tons per year. Employing UF and RO systems further reduced wastewater discharge volume by 15,600 tons.
  • Lower carbon emissions. Converting the fixed frequency of chilled water pumps and cooling water pumps to variable frequency enabled us to reduce 625 tons of CO2 equivalent per year. Energy efficiency lights are installed throughout the factory premises, further reducing 793 tons of CO2 equivalent per year.
  • Waste reduction. Establishing a central chemical delivery system helped reduce the use of 1,208 chemical barrels per year. We also reduced photoresist coating usage by 14,400 liters per year. Gold and copper reuse amounted to 474.45 kg per year. Wafer cassette reuse amounted to 39,795 pieces per year.

Building certifications as of August 31, 2017

  • LEED rating：Kaohsiung K12, K21, K22, K23, K26；Chung Li Buildings K and L；Shanghai Headquarters
  • EEWH rating：Kaohsiung K3, K4, K5, K7, K11, K12, K14B(water recycling facility), K15, K16, K21, K26；Chung Li Building A
  • Green Factory Label：Kaohsiung K3, K5, K7, K11, K12, K15
  • In progress: The construction of our new K24 building in Kaohsiung has taken into consideration of ‘low carbon footprint building’ methodologies from the transportation of materials, equipment, type of material used, renovation, dismantling and the entire building’s life cycle.

A new device being developed by Washington State University physicist Yi Gu could one day turn the heat generated by a wide array of electronics into a usable fuel source.

The device is a multicomponent, multilayered composite material called a van der Waals Schottky diode. It converts heat into electricity up to three times more efficiently than silicon — a semiconductor material widely used in the electronics industry. While still in an early stage of development, the new diode could eventually provide an extra source of power for everything from smartphones to automobiles.

“The ability of our diode to convert heat into electricity is very large compared to other bulk materials currently used in electronics,” said Gu, an associate professor in WSU’s Department of Physics and Astronomy. “In the future, one layer could be attached to something hot like a car exhaust or a computer motor and another to a surface at room temperature. The diode would then use the heat differential between the two surfaces to create an electric current that could be stored in a battery and used when needed.”

Gu recently published a paper on the Schottky diode in The Journal of Physical Chemistry Letters.

A new kind of diode

In the world of electronics, Schottky diodes are used to guide electricity in a specific direction, similar to how a valve in a water main directs the flow of liquid going through it. They are made by attaching a conductor metal like aluminum to a semiconductor material like silicon.

Instead of combining a common metal like aluminum or copper with a conventional semiconductor material like silicon, Gu’s diode is made from a multilayer of microscopic, crystalline Indium Selenide. He and a team of graduate students used a simple heating process to modify one layer of the Indium Selenide to act as a metal and another layer to act as a semiconductor. The researchers then used a new kind of confocal microscope developed by Klar Scientific, a start-up company founded in part by WSU physicist Matthew McCluskey, to study their materials’ electronic properties.

Unlike its conventional counterparts, Gu’s diode has no impurities or defects at the interface where the metal and semiconductor materials are joined together. The smooth connection between the metal and semiconductor enables electricity to travel through the multilayered device with almost 100 percent efficiency.

“When you attach a metal to a semiconductor material like silicon to form a Schottky diode, there are always some defects that form at the interface,” said McCluskey, a co-author of the study. “These imperfections trap electrons, impeding the flow of electricity. Gu’s diode is unique in that its surface does not appear to have any of these defects. This lowers resistance to the flow of electricity, making the device much more energy efficient.”

Next steps

Gu and his collaborators are currently investigating new methods to increase the efficiency of their Indium Selenide crystals. They are also exploring ways to synthesize larger quantities of the material so that it can be developed into useful devices.

“While still in the preliminary stages, our work represents a big leap forward in the field of thermoelectrics,” Gu said. “It could play an important role in realizing a more energy-efficient society in the future.”

A group of international physicists, jointly with NUST MISIS researchers, have conducted a series of experiments on graphene bombardment by swift heavy ions. The experimental results show that such a bombardment allows for the creation of nanopores in graphene. The diameter of these nanopores can be adjusted in a range of 1 to 4 nanometers.

The experimental results on graphen bombardment by swift heavy ions, conducted by NUST MISIS scientists together with colleagues from the University of Helsinki and Aalto University (Finland), the University of Nottingham (the United Kingdom), the University of Duisburg-Essen (Germany), the University of Vienna (Austria), the Center of Research on Ions, Materials and Photonics CIMAP (France), Ruder Boskovic Institute (Croatia), and the Institute of Ion Beam Physics & Materials Research (Germany) have been published in Carbon journal.

The experimental results on grapheme bombardment with a large amount of ions of different masses of C, O, Si, I, Au, Ta, Xe with high-energy  (up to 91 MeV) have shown that it is possible to create nanopores with a diameter from 1 to 4 nm when changing the energy of ions. Information on the dependence of nanopores on the energy of ions brings scientists closer to a controlled obtainment of such structures.

“We have experimentally and theoretically studied the process of nanopores occurrence (pores) in graphene after interaction between graphene with ions, as well as studying the dependence of pores` sizes on the type and ions` energy, and the nature of the appearance of these defects in grapheme have been explained,” said Arkady Krasheninikov, visiting Professor at NUST MISIS, Candidate of Physical and Mathematical Sciences, research author, and head of the ‘Minimization of degradation of two-dimensional inorganic materials with the use of atomistic calculations’ project.

According to Krasheninikov, “The current development of grapheme research is connected with studies of the possibility of controlled changes of its properties, for example by introduction of defects in its structure. The creation of defects in graphene can significantly change its electronic and conductive properties, and even lead to the induction of magnetism. One of the possible ways of introducing defects into a graphene structure is a bombardment of ions of different elements.”

Krasheninikov also added that scientists have been interested in nanoporous graphene for quite a while. He believes that the obtained nanostructures can be widely used in various fields of science and technology, in particular in the capacity of materials for the purification of liquids, DNA sequencing, etc.

“One expects that with a regular arrangement of pores in graphene, its spectrum would be readjusted into a semiconductive state and that would allow us to use it in electronics,” added Krasheninikov.

 

Many next-generation electronic and electro-mechanical device technologies hinge on the development of ferroelectric materials. The unusual crystal structures of these materials have regions in their lattice, or domains, that behave like molecular switches. The alignment of a domain can be toggled by an electric field, which changes the position of atoms in the crystal and switches the polarization direction. These crystals are typically grown on supporting substrates that help to define and organize the behavior of domains. Control over the switching of domains when making crystals of ferroelectric materials is essential for any future applications.

Now an international team by Nagoya University has developed a new way of controlling the domain structure of ferroelectric materials, which could accelerate development of future electronic and electro-mechanical devices.

“We grew lead zirconate titanate films on different substrate types to induce different kinds of physical strain, and then selectively etched parts of the films to create nanorods,” says lead author Tomoaki Yamada. “The domain structure of the nanorods was almost completely flipped compared with [that of] the thin film.”

Lead zirconate titanate is a common type of ferroelectric material, which switches based on the movement of trapped lead atoms between two stable positions in the crystal lattice. Parts of the film were deliberately removed to leave freestanding rods on the substrates. The team then used synchrotron X-ray radiation to probe the domain structure of individual rods.

The contact area of the rods with the substrate was greatly reduced and the domain properties were influenced more by the surrounding environment, which mixed up the domain structure. The team found that coating the rods with a metal could screen the effects of the air and they tended to recover the original domain structure, as determined by the substrate.

“There are few effective ways of manipulating the domain structure of ferroelectric materials, and this becomes more difficult when the material is nanostructured and the contact area with the substrate is small.” says collaborator Nava Setter. “We have learned that it’s possible to nanostructure these materials with control over their domains, which is an essential step towards the new functional nanoscale devices promised by these materials.”

The article, “Charge screening strategy for domain pattern control in nanoscale ferroelectric systems,” was published in Scientific Reports at DOI:10.1038/s41598-017-05475-x

 

IC Insights has revised its outlook for semiconductor industry capital spending and presented its new findings in the August Update to The McClean Report 2017.  IC Insights’ latest forecast is for semiconductor industry capital spending to climb 20% this year.

Figure 1 shows the steep upward trend of quarterly capital spending in the semiconductor industry since 1Q16. Although there was a slight pause in the upward trajectory in 1Q17, 2Q17 set a new record for quarterly spending outlays.   Moreover, 1H17 semiconductor industry spending was 48% greater than in 1H16.  IC Insights believes that whether industry-wide capital spending in the second half of 2017 can match the first half of the year is greatly dependent upon the level of Samsung’s 2H17 spending outlays.

Not only has Samsung Semiconductor been on a tear with regard to its semiconductor sales, surging into the number one ranking in 2Q17, but the company has also been on a tremendous capital spending spree for its semiconductor division this year.  As depicted in Figure 2, Samsung spent a whopping $11.0 billion in capital outlays for its semiconductor group in 1H17, more than 3x greater than the company spent in 1H16 and only $300 million less than the company spent in all of 2016!   In fact, Samsung’s capital expenditures in 1H17 represented 25% of the total semiconductor industry capital spending and 28% of the outlays in 2Q17.

While the company has publicly reported that it spent $11.0 billion in capital outlays for its semiconductor division in 1H17 (a $22.0 billion annual run-rate), Samsung has been very secretive about revealing its full-year 2017 budget for its semiconductor group (it might be afraid of shocking the industry with such a big number!).  In 2012, the year of Samsung’s previous first half spending surge before 1H17, the company cut its second half capital outlays by more than 50%, from $8.5 billion in 1H12 to $3.7 billion in 2H12.  Will the company follow the same pattern in 2017?  At this point, it is impossible to tell.  IC Insights believes that Samsung’s full-year 2017 capital expenditures could range from $15.0 billion to $22.0 billion!

Figure 1

Figure 1

If Samsung spends $22.0 billion in capital outlays this year, total semiconductor industry capital spending could reach $85.4 billion, which would represent a 27% increase over the $67.3 billion the industry spent in 2016.

It is interesting to note that two of the major spenders, TSMC and Intel, are expected to move in opposite directions with regard to their 2H17 capital spending plans. TSMC spent about $6.8 billion in capital outlays in 1H17. If it sticks to its $10.0 billion budget this year, which it reiterated in its second quarter results, it would only spend about $3.2 billion in 2H17, less than half its outlays in 1H17. In contrast, Intel spent only about $4.7 billion in 1H17, leaving the company to spend about $7.3 billion in 2H17 in order to reach its stated full-year 2017 spending budget of $12.0 billion.

Figure 2

Figure 2

The global semiconductor advanced packaging market is expected to grow at a CAGR of 8.45% during the period 2017-2021, according to the “Global Semiconductor Advanced Packaging Market 2017-2021” report by Research and Markets.

The latest trend gaining momentum in the market is changes in wafer size. The semiconductor industry has seen a drastic transition in wafer size over the last five decades (1910-2016). The industry is focusing on producing larger diameter wafers, which is expected to cut down the manufacturing cost by 20%-25%.

According to the report, one of the other major drivers for this market is complex semiconductor IC designs. The number of features and functionalities offered by consumer electronic devices is on the rise as electronic device manufacturers look to differentiate their offerings from those of competitors.

Further, the report states that one of the major factors hindering the growth of this market is rapid technological changes. The rapid technological advancements in wafer processing have always been a major challenge faced by vendors in the semiconductor advanced packaging market. The semiconductor industry is continuously seeing transitions, such as the miniaturization of nodes and the increase in wafer sizes with respect to ultra-large-scale integration (ULSI) fabrication technology.

Topological insulators, a class of materials which has been investigated for just over a decade, have been heralded as a new ‘wonder material’, as has graphene. But so far, topological insulators have not quite lived up to the expectations fueled by theoretical studies. University of Groningen physicists now have an idea about why. Their analysis was published on 27 July in the journal Physical Review B.

Topological insulators are materials that are insulating in the bulk but allow charge to flow across the surface. These conducting states at the surface originate from ordering patterns in the states where electrons reside that are different from ordinary materials. This ordering is linked to the physical concept of ‘topology’, analogous to that used in mathematics. This property gives rise to very robust states with some special properties.

Heavy atoms

For one, their spin — a magnetic property of electrons which can have the values ‘up’ or ‘down’ — is locked to their movement. ‘This means that electrons moving to the right have spin down, and those moving to the left have spin up’, explains first author of the study Eric de Vries, PhD student in the ‘Spintronics of Functional Materials’ research group led by his supervisor prof. dr. Tamalika Banerjee. This is group is part of the Zernike Institute for Advanced Materials. ‘But it also means that when you inject electrons with spin up into such a topological insulator, they will travel to the left!’ Topological insulators might therefore be very useful in the realization of spintronics: electronics based on the quantized spin value rather than the charge of electrons.

The special properties of topological insulators are predicted by the theoretical analysis of the surface structures of these materials, made from crystals of heavy atoms. But experiments show mixed results, which don’t quite live up to the theoretical predictions. ‘We wondered why, so we devised experiments to investigate the behaviour of the surface state electrons. Specifically, we wanted to see if transport is really limited to the surface, or if it is also present in the bulk of the material.’

Surprising

Earlier experiments by the group, in which they used ferromagnets to detect the spins of electrons generated in the topological insulator, were surprising, says De Vries. ‘We demonstrated that a voltage presumably originating from spin detection can originate in factors other than the locking of electron spin to its movement. Using different geometries, we showed that artefacts related to stray magnetic fields generated by the ferromagnets can mimic similar spin voltages.’ This observation may lead to a re-evaluation of some published results.

This time, they used a different approach. ‘We analyzed the topological insulators using strong magnet fields. This causes electrons to oscillate in transport channels.’ De Vries went to the national High Field Magnet Laboratory at the Radboud University Nijmegen, where a 33-Tesla magnet is available, one of the stronger magnets in the world. ‘Others have done similar tests with weaker magnets, but these are not sensitive enough to reveal the additional transport channels that coexist with the surface states.’ De Vries’s experiments showed that a considerable part of the charge transport occurred in the bulk phase of the material, and not only at the surface.

Transport channels

The reason for this, explains De Vries, is the imperfect crystal structure of the topological insulator. ‘Sometimes there are atoms missing in the crystal structure. This results in freely moving electrons. These start to conduct as new transport channels, generating electric current in the bulk of the material.’

So why has no one noted this before? De Vries stresses that interpreting transport measurements made on topological insulators can be difficult. ‘We experienced this in our previous experiments. Our message is that extreme care is needed in the interpretation of experimental observations for devices based on these materials.’ Also, experiments which might lead to clearer conclusions require very high magnetic fields in specialized labs.

Glitches

The results point to a way to improve topological insulators. ‘The key is to grow the crystals without any missing atoms. Another solution is to fill the holes, for example with calcium ions that bind the free electrons. But that might cause other disturbances to the electrons’ mobility.’ For ten years, topological insulators were all the rage. They were compared to the wonder material graphene. The discovery that, in practice, topological insulators have glitches serves as a reality check. De Vries: ‘We need to study and understand the interaction between the surface states and the bulk material in much more detail.’

Advances in modern electronics has demanded the requisite hardware, transistors, to be smaller in each new iteration. Recent progress in nanotechnology has reduced the size of silicon transistors down to the order of 10 nanometers. However, for such small transistors, other physical effects set in, which limit their functionality. For example, the power consumption and heat production in these devices is creating significant problems for device design. Therefore, novel quantum materials and device concepts are required to develop a new generation of energy-saving information technology. The recent discoveries of topological materials — a new class of relativistic quantum materials — hold great promise for use in energy saving electronics.

Researchers in the Louisiana Consortium for Neutron Scattering, or LaCNS, led by LSU Department of Physics & Astronomy Chair and Professor John F. DiTusa and Tulane University Professor Zhiqiang Mao, with collaborators at Oak Ridge National Lab, the National High Magnetic Field Laboratory, Florida State University, and the University of New Orleans, recently reported the first observation of this topological behavior in a magnet, Sr1-yMn1-zSb2 (y, z < 0.1). These results were published this week in Nature Materials(doi:10.1038/nmat4953).

“This first observation is a significant milestone in the advancement of novel quantum materials and this discovery opens the opportunity to explore its consequences. The nearly massless behavior of the charge carriers offers possibilities for novel device concepts taking advantage of the extremely low power dissipation,” DiTusa said.

The phrase “topological materials” refers to materials where the current carrying electrons act as if they have no mass similar to the properties of photons, the particles that make up light. Amazingly, these electronic states are robust and immune to defects and disorder because they are protected from scattering by symmetry. This symmetry protection results in exceedingly high charge carrier mobility, creating little to no resistance to current flow. The result is expected to be a substantial reduction in heat production and energy saving efficiencies in electronic devices.

This new magnet displays electronic charge carriers that have almost no mass. The magnetism brings with it an important symmetry breaking property – time reversal symmetry, or TRS, breaking where the ability to run time backward would no longer return the system back to its starting conditions. The combination of relativistic electron behavior, which is the cause of much reduced charge carrier mass, and TRS breaking has been predicted to cause even more unusual behavior, the much sought after magnetic Weyl semimetal phase. The material discovered by this collaboration is thought to be an excellent one to investigate for evidence of the Weyl phase and to uncover its consequences.

A key step in unlocking the potential for greener, faster, smaller electronic circuitry was taken recently by a group of researchers led by UAlberta physicist Robert Wolkow.

The research team found a way to delete and replace out-of-place atoms that had been preventing new revolutionary circuitry designs from working. This unleashes a new kind of silicon chips for used in common electronic products, such as our phones and computers.

“For the first time, we can unleash the powerful properties inherent to the atomic scale,” explained Wolkow, noting that printing errors on silicon chips are inevitable when working at the atomic scale. “We were making things that were close to perfect but not quite there. Now that we have the ability to make corrections, we can ensure perfect patterns, and that makes the circuits work. It is this new ability to edit at the atom scale that makes all the difference.”

Think of a typing mistake and the ability to go back and white it out and type it again perfectly. Now imagine that the white out is actually single hydrogen atoms, allowing a level of precision previously unattainable.

“We can precisely erase any errors and reprint that atom in the correct place. It’s not even a compromise like white out where you either have a gooey layer or indentation. It’s actually perfect,” said Wolkow, who worked with fellow scientists from the University of Alberta, the National Research Council, and Quantum Silicon Inc.

Scientists have seen many hints that atomic circuitry was within reach. However, the necessary precision was previously possible only for simple materials that had to be maintained at ultra-low temperatures, impractical for everyday applications demanded in computers and personal digital devices. Wolkow and his team have discovered methods and material to ensure stability at room temperature, challenges that he and other scientists the world over have been working for decades on overcoming.

Wolkow’s graduate students Roshan Achal and Taleana Huff together with postdoc Moe Rashidi showed they can overcome these obstacles with a modified approach to the same silicon chips that are used in today’s circuitry. While they had previously improved accuracy of atomic silicon printing, errors in the form of misplaced atoms always occurred at the one percent level. Though the placement errors were small–about one third of a nanometer–they nevertheless large enough to upset circuit operation.

The students created a reliable procedure for picking up single hydrogen atoms with their atomically sharp probe and replacing one or more hydrogen atoms to perfectly erase atomic misprints.

With their new discovery, many remaining challenges to ultra-low power atomic circuitry have also been erased. Wolkow, Achal, and Huff’s discovery has been captured in the academic paper “Atomic Whiteout,” appearing in the scientific journal ACS Nano.

 

A team of physicists featuring researchers from MIPT and ITMO University has conducted a comparative analysis of a range of materials to determine if they are applicable to dielectric nanophotonics. Their systematic study produced results that can optimize the use of known materials for building optical nanodevices, as well as encourage the search for new materials with superior properties.

In order to send, receive, and process electromagnetic signals, antennas are used. An antenna is a device capable of effectively transmitting, picking up, and redirecting electromagnetic radiation. Typically, one thinks of antennas as macroscopic devices operating in the radio and microwave range. However, there are similar optical devices. The wavelengths of visible light amount to several hundred nanometers. As a consequence, optical antennas are, by necessity, nanosized devices. Optical nanoantennas, which can focus, direct, and effectively transmit light, have a wide range of applications, including information transmission over optical channels, photodetection, microscopy, biomedical technology, and even speeding up chemical reactions.

For an antenna to pick up and transmit signals efficiently, its elements need to be resonant. In the radio band, such elements are pieces of wire. In the optical range, silver and gold nanoparticles with plasmonic resonances have long been used for this purpose. Electromagnetic fields in such particles can be localized on a scale of 10 nanometers or less, but most of the energy of the field is wasted due to Joule heating of the conducting metal. There is an alternative to plasmonic nanoparticles, which has been studied extensively for the last five years, namely particles of dielectric materials with high refractive indices at visible light frequencies, such as silicon. When the size of the dielectric particle and the wavelength of light are just right, the particle supports optical resonances of a particular kind, called Mie resonances. Because the material properties of dielectrics are different from those of metals, it is possible to significantly reduce resistive heating by replacing plasmonic nanoantennas with dielectric analogs.

The key characteristic of a material determining Mie resonance parameters is the refractive index. Particles made of materials with high refractive indices have resonances characterized by high quality factors. This means that in these materials electromagnetic oscillations last longer without external excitation. In addition, higher refractive indices correspond to smaller particle diameters, allowing for more miniature optical devices. These factors make high-index materials — i.e., those with high indices of refraction — more suitable for the implementation of dielectric nanoantennas.

In their paper published in Optica, the researchers systematically examine the available high-index materials in terms of their resonances in the visible and infrared spectral ranges. Materials of this kind include semiconductors and polar crystals, such as silicon carbide. To illustrate the behavior of various materials, the authors present their associated quality factors, which indicate how quickly oscillations excited by incident light die out. Theoretical analysis enabled the researchers to identify crystalline silicon as the best currently available material for the realization of dielectric antennas operating in the visible range, with germanium outperforming other materials in the infrared band. In the mid-infrared part of the spectrum, which is of particular interest due to possible applications, such as radiative cooling, i.e., the cooling of a heated body by means of radiating heat in the form of electromagnetic waves into the environment; and thermal camouflage — reducing thermal radiation given off by an object, thus making it invisible to infrared cameras, the compound of germanium and tellurium took the pedestal.

There are fundamental limitations on the value of the quality factor. It turns out that high refractive indices in semiconductors are associated with interband transitions of electrons, which inevitably entail the absorption of energy carried by the incident light. This absorption in turn leads to a reduction of the quality factor, as well as heating, and that is precisely what the researchers are trying to get rid of. There is, therefore, a delicate balance between a high index of refraction and energy losses.

“This study is special both because it offers the most complete picture of high-index materials, showing which of them is optimal for fabricating a nanoantenna operating in this spectral range, and because it provides an analysis of the manufacturing processes involved,” notes Dmitry Zuev, research scientist at the Metamaterials laboratory of the Faculty of Physics and Engineering, ITMO University. “This enables a researcher to select a material, as well as the desired manufacturing technique, taking into account the requirements imposed by their specific situation. This is a powerful tool furthering the design and experimental realization of a wide range of dielectric nanophotonic devices.”

According to the overview of manufacturing techniques, silicon, germanium, and gallium arsenide are the most thoroughly studied high-index dielectrics used in nanophotonics. A wide range of methods are available for manufacturing resonant nanoantennas based on these materials, including lithographic, chemical, and laser-assisted methods. However, in the case of some materials, no technology for fabrication of resonant nanoparticles has been developed. For example, researchers have yet to come up with ways of making nanoantennas from germanium telluride, whose properties in the mid-infrared range were deemed the most attractive by the theoretical analysis.

“Silicon is currently, beyond any doubt, the most widely used material in dielectric nanoantenna manufacturing,” says Denis Baranov, a PhD student at MIPT. “It is affordable, and silicon-based fabrication techniques are well established. Also, and this is important, it is compatible with the CMOS technology, an industry standard in semiconductor engineering. But silicon is not the only option. Other materials with even higher refractive indices in the optical range might exist. If they are discovered, this would mean great news for dielectric nanophotonics.”

The research findings obtained by the team could be used by nanophotonics engineers to develop new resonant nanoantennas based on high-index dielectric materials. Besides, the paper suggests further theoretical and experimental work devoted to the search for other high-index materials with superior properties to be used in new improved dielectric nanoantennas. Such materials could, among other things, be used to considerably boost the efficiency of radiative cooling of solar cells, which would constitute an important technological advance.