Yearly Archives: 2015

Hybrid optoelectronic devices based on blends of hard and soft semiconductors can combine the properties of the two material types, opening the possibility for devices with novel functionality and properties, such as cheap and scalable solution-based processing methods. However, the efficiency of such devices is limited by the relatively slow electronic communication between the material components that relies on charge transfer, which is susceptible to losses occurring at the hybrid interface.

A phenomenon called Förster resonant energy transfer (FRET) was recently theoretically predicted and experimentally observed in hybrid structures combining an inorganic quantum well with a soft semiconductor film. Förster resonant energy transfer is a radiationless transmission of energy that occurs on the nanometer scale from a donor molecule to an acceptor molecule. The process promotes energy rather than charge transfer, providing an alternative contactless pathway that avoids some of the losses caused by charge recombination at the interface.

Now researchers from the University of Cyprus and Cyprus University of Technology, along with colleagues from the University of Crete, Greece have conducted a comprehensive investigation on how various structural and electronic parameters affect FRET in structures of nitride quantum wells with light-emitting polymers. Based on their studies, the researchers discuss the process to optimize the energy transfer process and identify the limitations and implications of the Förster mechanism in practical devices. The work demonstrates the importance of understanding FRET in hybrid structures that could pave the way for developing novel devices such as high-efficiency LEDs and solar cells. The researchers present their work in a paper published this week in the Journal of Chemical Physics, from AIP Publishing.

In the top left is a schematic of Förster Resonant Energy Transfer from a near-surface nitride quantum well to a polymer overlayer. In the top right is fluorescence from solutions containing light emitting polymer materials. In the bottom left high resolution transmission electron microscope image from an InGaN/GaN quantum well. In the bottom right absorption and fluorescence spectra from various polymers used in our study. Credit: Grigorios Itskos/University of Cyprus, Cyprus

In the top left is a schematic of Förster Resonant Energy Transfer from a near-surface nitride quantum well to a polymer overlayer. In the top right is fluorescence from solutions containing light emitting polymer materials. In the bottom left high resolution transmission electron microscope image from an InGaN/GaN quantum well. In the bottom right absorption and fluorescence spectra from various polymers used in our study. Credit: Grigorios Itskos/University of Cyprus, Cyprus

“Pioneering theoretical and experimental work has demonstrated that energy can be efficiently transferred across hybrid semiconductors via the Förster mechanism. However, our understanding is not complete and many material and structural parameters affecting FRET in such hybrids remain unexplored. Our work employs for a first time a comprehensive approach that combines fabrication, theoretical modeling and optical spectroscopy to fully understand FRET in a nitride quantum well-polymer hybrid structure,” said Grigorios Itskos, the primary researcher and an assistant professor from the Department of Physics at the University of Cyprus.

“We used a systematic approach to optimize the FRET efficiency by tuning various parameters of the nitride quantum well component. The process allowed us to study unexplored aspects of the mechanism and identify competing mechanisms that limit the energy transfer efficiency in hybrid planar structures. The outcome of our investigation can guide future efforts towards a rational design of hybrid geometries that can optimize FRET and limit competing losses to render FRET-based devices feasible,” he said.

Itskos noted that the researchers chose to study structures based on nitrides because the material is well-researched and is used in niche applications such as blue light emitting LEDs. “However, the functionality [of nitride structures] can be further increased by combining them with other soft semiconductors such as light-emitting polymers. The spectral tunability and high light-absorption and emitting efficiency of the polymers can be exploited to demonstrate efficient down-conversion of the blue nitride emission, providing a scheme for efficient hybrid LEDs,” Itskos said.

In the study, the researchers initially sought to produce and study near-surface nitride quantum wells to allow a close proximity with the light-emitting polymer deposited on their top surface.

“The nanoscale proximity promotes efficient interactions between the excitations of the two materials, leading to fast Förster transfer that can compete with the intrinsic recombination of the excitations,” Itskos explained. Förster resonant energy transfer is a strongly distance-dependent process which occurs over a scale of typically 1 to 10 nanometers. The contactless pathway of energy transmission could avoid energy losses associated with charge recombination and transport in hybrid structures.

Using a sequence of growth runs, theoretical modeling and luminescence spectroscopy (a spectrally-resolved technique measuring the light emission of an object), the researchers identified the way to optimize the surface quantum well emission.

“We studied the influence of parameters such as growth temperature, material composition, and thickness of the quantum well and barrier on the optoelectronic properties of the nitride structures. Increase of the quantum confinement by reducing the width or increasing the barrier of the quantum well increases the well emission. However, for high quantum well confinement, excitations leak to the structure surface, quenching the luminescence. So there is an optimum set of quantum well parameters that produce emissive structures,” Itskos said. He also pointed out that the studies indicate a strong link between the luminescence efficiency of the nitride quantum well with the FRET efficiency of the hybrid structure, as predicted by the basic theory of Förster. The correlation could potentially provide an initial and simple FRET optimization method by optimizing the luminescent efficiency of the energy donor in the absence of the energy acceptor material.

“Our studies also indicated that electronic doping of the interlayer between the nitride quantum well and the polymer film reduces the efficiency of FRET. This constitutes a potential limitation for the implementation of such hybrid structures in real-world electronic devices, as electronic doping is required to produce efficient practical devices. Further studies are needed to establish the exact influence of doping on FRET,” Itskos noted.

He said the team’s next step is to perform a systematic study of hybrid structures based on doped nitride quantum wells to investigate the mechanisms via which electronic doping affects the characteristics of the Förster resonant energy transfer.

IC Insights will release its new 2016 McClean Report late next month.  The 2016 McClean Report will include a ranking of the top-50 semiconductor suppliers’ for 2015 as well as the top-50 fabless semiconductor suppliers.  The forecasted “post-merger” top-10 2015 IDM and fabless semiconductor suppliers are covered in this research bulletin.

Unlike the relatively close annual market growth relationship between fabless semiconductor suppliers and foundries, fabless semiconductor company sales growth versus IDM (integrated device manufacturers) semiconductor supplier growth has typically been very different (Figure 1).  In 2010, for the first and only time on record thus far, IDM semiconductor sales growth (35%) outpaced fabless semiconductor company sales growth (29%).  Since very few fabless semiconductor suppliers participate in the memory market, the fabless suppliers did not receive much of a boost from the surging DRAM and NAND flash memory markets in 2010, which grew 75% and 44%, respectively.

As shown in Figure 2, only three of the top-10 IDM semiconductor suppliers are forecast to register growth in 2015 and, in total, the top-10 IDMs are expected to display flat growth this year.  Although flat growth by the top-10 IDMs would typically be considered poor performance, it is still forecast to be a much better result than is expected from the top-10 fabless semiconductor suppliers (Figure 3).  In order to make direct comparisons for year-over-year growth, IC Insights combined the merged, or soon to be merged, companies’ 2014 and 2015 semiconductor sales regardless of when the merger occurred.

As shown, the top-10 fabless semiconductor suppliers are forecast to register a 5% decline in sales this year, five points worse than the top-10 IDMs.  It should be noted that essentially all of the decline expected for the top-10 fabless suppliers in 2015 could be attributed to the forecasted decline in Qualcomm/CSR’s sales this year.  Much of the sharp decline in Qualcomm/CSR’s sales this year is being driven by Samsung’s increasing use of its internally developed Exynos application processor in its smartphones instead of the application processors it had previously sourced from Qualcomm.

Fig 1

Fig 1

Fig 2

Fig 2

Fig 3

Fig 3

Application processor sales to fabless/system house Apple from pure-play foundry TSMC are included in the fabless company sales ranking under the “Apple/TSMC” moniker.  Application processor sales supplied to Apple from IDM-foundry Samsung are included as part of Samsung’s logic IC sales.

As mentioned in the title of this Research Bulletin, 2015 could end up being only the second year ever, after 2010, in which the IDM semiconductor suppliers outpace the fabless semiconductor suppliers with regard to year-over-year growth.  Whether this actually takes place will be revealed from IC Insights’ extended compilation of the IDM and fabless semiconductor company rankings for the 2016 McClean Report.

SEMI Foundation, created by global industry association SEMI to support education and career awareness in the field of high-tech, has announced the appointment of Leslie Tugman as its executive director. SEMI Foundation is known for its flagship program, SEMI High Tech U, which serves high school students interested in pursuing careers in science, technology, engineering and math. Plans are underway to expand SEMI Foundation’s activities under Tugman’s leadership to include workforce development programs.

“Leslie has been a key member of the SEMI Foundation team for the past 15 years, helping delivering over 190 High Tech U programs that have reached more than 6,000 students and teachers since the foundation’s inception in 2002,” said Art Zafiropoulo, chairman and CEO of Ultratech, and founding member of the SEMI Foundation board of directors. “Leslie’s thorough understanding of the High Tech U program and her passion and experience for workforce development will ensure continuity and quality of programs as we look to expand the foundation’s activities as part of our 2020 strategic initiatives.”

SEMI has long been at the center of the electronics supply chain representing its more than 1,900 corporate members.  As the electronics supply chain has become increasingly interdependent, SEMI’s platforms have been ever more relied on to bring the extended electronics supply chain together for collaboration.  Additionally, SEMI recently named FlexTech as a Strategic Association Partner providing this vital Flexible Hybrid Electronics community access to SEMI’s global platforms and adjacent opportunities for SEMI members. Now that the SEMI Foundation is a mature entity with established leadership, it is well-positioned to expand in complementary new directions.

“I am excited about this appointment, and look forward to the opportunity to work with the board and take the SEMI Foundation to the next level,” said Tugman. “The foundation is more than High Tech U; we are embarking on workforce development initiatives that address the pipeline for members in a near-term way.”

While with SEMI High Tech U, Tugman was president of WorkForce Resources, Inc.  Prior to that, she served as the business development director for Business Education Compact in Portland, Oregon, delivering workforce development programs focused on educator internships. Career milestones include deputy executive directorship of the Texas Water Development Board, and assistant land commissioner with the Texas General Land Office.

SEMI High Tech U provides secondary school students with an intensive, industry-led introduction to the high tech industry, potential career paths and education requirements to meet their goals.

SEMI High Tech U provides secondary school students with an intensive, industry-led introduction to the high tech industry, potential career paths and education requirements to meet their goals.

Students and teachers participate in hands-on activities that focus on topics including statistics, nanotechnology, solar and alternative energy technologies, electronics and mathematics. Students also work on soft skills and participate in mock job interviews with industry professionals.

Students and teachers participate in hands-on activities that focus on topics including statistics, nanotechnology, solar and alternative energy technologies, electronics and mathematics. Students also work on soft skills and participate in mock job interviews with industry professionals.

Renesas Electronics Corporation, a supplier of advanced semiconductor solutions, today announced that it has decided on a policy of consolidation for the Kochi Factory (Konan, Kochi Prefecture) of its wholly owned subsidiary, Renesas Semiconductor Manufacturing Co., Ltd. Under this consolidation policy, the factory is to be closed within the next two to three years, and production of the products currently being manufactured there will be transferred to other facilities within the Renesas Group or, in the case of some products, phased out. In the news release, Renesas Electronics Shows Direction of Renesas Group, announced on August 2, 2013, Renesas Electronics indicated its intention with regard to the Kochi Factory to continue production, downsizing to be appropriate scale. However, after reexamining the present production load situation and the likely future production load, Renesas has concluded that the production load will be less than was initially anticipated and that maintaining the profitability of the Kochi Factory will be problematic.

Efforts were made to boost production efficiency at the Kochi Factory or to find another company willing to purchase it, however, at present there appears to be no way to compensate for the reduction in the production load. Therefore, Renesas has decided on a policy of consolidation for the Kochi Factory.

Negotiations are planned between labor and management regarding the treatment of the factory’s employees during and after the consolidation, though every effort will be made to ensure continued employment of the affected personnel, with the assistance of Kochi Prefecture.

In addition, with regard to the utilization of the Kochi Factory following the consolidation, Renesas will endeavor to secure a purchaser for the facility with the assistance of Kochi Prefecture.

Physicists at the Technical University of Munich, the Los Alamos National Laboratory and Stanford University (USA) have tracked down semiconductor nanostructure mechanisms that can result in the loss of stored information – and halted the amnesia using an external magnetic field. The new nanostructures comprise common semiconductor materials compatible with standard manufacturing processes.

Quantum bits, qubits for short, are the basic logical elements of quantum information processing (QIP) that may represent the future of computer technology. Since they process problems in a quantum-mechanical manner, such quantum computers might one day solve complex problems much more quickly than currently possible, so the hope of researchers.

In principle, there are various possibilities of implementing qubits: photons are an option equally as viable as confined ions or atoms whose states can be altered in a targeted manner using lasers. The key questions regarding their potential use as memory units are how long information can be stored in the system and which mechanisms might lead to a loss of information.

A team of physicists headed by Alexander Bechtold and Professor Jonathan Finley at the Walter Schottky Institute of the Technical University of Munich and the Cluster of Excellence Nanosystems Initiative Munich (NIM) have now presented a system comprising a single electron trapped in a semiconductor nanostructure. Here, the electron’s spin serves as the information carrier.

By evaporating indium gallium arsenide onto a gallium arsenide substrate TUM physicists created nanometer-scale hills, so-called quantum dots. An electron trapped in one of these quantum dots can be used to store information. Hitherto unknown memory loss mechanisms could be switched off by applying a magnetic field. Credit: Fabian Flassig / TUM

By evaporating indium gallium arsenide onto a gallium arsenide substrate TUM physicists created nanometer-scale hills, so-called quantum dots. An electron trapped in one of these quantum dots can be used to store information. Hitherto unknown memory loss mechanisms could be switched off by applying a magnetic field. Credit:
Fabian Flassig / TUM

The researchers were able to precisely demonstrate the existence of different data loss mechanisms and also showed that stored information can nonetheless be retained using an external magnetic field.

Electrons trapped in a quantum dot

The TUM physicists evaporated indium gallium arsenide onto a gallium arsenide substrate to form their nanostructure. As a result of the different lattice spacing of the two semiconductor materials strain is produced at the interface between the crystal grids. The system thus forms nanometer-scale “hills” – so-called quantum dots.

When the quantum dots are cooled down to liquid helium temperatures and optically excited, a singe electron can be trapped in each of the quantum dots. The spin states of the electrons can then be used as information stores. Laser pulses can read and alter the states optically from outside. This makes the system ideal as a building block for future quantum computers.

Spin up or spin down correspond to the standard logical information units 0 and 1. But, on top of this come additional intermediate states of quantum mechanical up and down superpositions.

Hitherto unknown memory loss mechanisms

However, there is one problem: “We found out that the strain in the semiconductor material leads to a new and until recently unknown mechanism that results in the loss of quantum information,” says Alexander Bechtold. The strain creates tiny electric fields in the semiconductor that influence the nuclear spin orientation of the atomic nuclei.

“It’s a kind of piezoelectric effect,” says Bechthold. “It results in uncontrolled fluctuations in the nuclear spins.” These can, in turn, modify the spin of the electrons, i.e. the stored information. The information is lost within a few hundred nanoseconds.

In addition, Alexander Bechthold’s team was able to provide concrete evidence for further information loss mechanisms, for example that electron spins are generally influenced by the spins of the surrounding 100,000 atomic nuclei.

Preventing quantum mechanical amnesia

“However, both loss channels can be switched off when a magnetic field of around 1.5 tesla is applied,” says Bechtold. “This corresponds to the magnetic field strength of a strong permanent magnet. It stabilizes the nuclear spins and the encoded information remains intact.”

“Overall, the system is extremely promising,” according to Jonathan Finley, head of the research group. “The semiconductor quantum dots have the advantage that they harmonize perfectly with existing computer technology since they are made of similar semiconductor material.” They could even be equipped with electrical contacts, allowing them to be controlled not only optically using a laser, but also using voltage pulses.

A new era of electronics and even quantum devices could be ushered in with the fabrication of a virtually perfect single layer of “white graphene,” according to researchers at the Department of Energy’s Oak Ridge National Laboratory.

Growth and transfer of 2-D material such as hexagonal boron nitride and graphene was performed by a team that included Yijing Stehle of Oak Ridge National Laboratory. Credit: ORNL

Growth and transfer of 2-D material such as hexagonal boron nitride and graphene was performed by a team that included Yijing Stehle of Oak Ridge National Laboratory. Credit: ORNL

The material, technically known as hexagonal boron nitride, features better transparency than its sister, graphene, is chemically inert, or non-reactive, and atomically smooth. It also features high mechanical strength and thermal conductivity. Unlike graphene, however, it is an insulator instead of a conductor of electricity, making it useful as a substrate and the foundation for the electronics in cell phones, laptops, tablets and many other devices.

“Imagine batteries, capacitors, solar cells, video screens and fuel cells as thin as a piece of paper,” said ORNL’s Yijing Stehle, postdoctoral associate and lead author of a paper published in Chemistry of Materials. She and colleagues are also working on a graphene hexagonal boron 2-D capacitor and fuel cell prototype that are not only “super thin” but also transparent.

With their recipe for white graphene, ORNL researchers hope to unleash the full potential of graphene, which has not delivered performance consistent with its theoretical value. With white graphene as a substrate, researchers believe they can help solve the problem while further reducing the thickness and increasing the flexibility of electronic devices.

While graphene, which is stronger and stiffer than carbon fiber, is a promising material for data transfer devices, graphene on a white graphene substrate features several thousand times higher electron mobility than graphene on other substrates. That feature could enable data transfers that are much faster than what is available today. “Imagine your message being sent thousands of times faster,” Stehle said.

Stehle noted that this work is especially significant because it takes the material beyond theory. A recent theoretical study led by Rice University, for instance, proposed the use of white graphene to cool electronics. Stehle and colleagues have made high-quality layers of hexagonal boron nitride they believe can be cost-effectively scaled up to large production volumes.

“Various hexagonal boron nitride single crystal morphology – triangle to hexagon – formulations have been mentioned in theoretical studies, but for the first time we have demonstrated and explained the process,” Stehle said.

That process consists of standard atmospheric pressure chemical vapor deposition with a similar furnace, temperature and time, but there’s a twist. The difference is what Stehle describes as “a more gentle, controllable way to release the reactant into the furnace and figuring out how to take advantage of inner furnace conditions. These two factors are almost always neglected.”

Stehle continued: “I just thought carefully beforehand and was curious. For example, I remind myself that there are many conditions in this experiment that can be adjusted and could make a difference. Whenever I see non-perfect results, I do not count them as another failure but, instead, another condition adjustment to be made. This ‘failure’ may become valuable.”

Co-authors of the paper. are Harry Meyer, Raymond Unocic, Michelle Kidder, Georgios Polizos, Panos Datskos, Roderick Jackson and Ivan Vlassiouk of ORNL and Sergei Smirnov of New Mexico State University. Funding was provided by the Laboratory Directed Research and Development program. A portion of the research was conducted at the Center for Nanophase Materials Science, a DOE Office of Science User Facility at ORNL.

UT-Battelle manages ORNL for the DOE’s Office of Science. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time.

Diodes reported that it has completed its acquisition of Pericom Semiconductor.

Diodes noted the merger agreement was initially announced on September 3, and Pericom shareholders approved the transaction at a special meeting of shareholders held on November 20. According to a release, the transaction closed and became effective today, with each share of Pericom being converted into the right to receive $17.75 in cash, without interest. The aggregate consideration will be approximately $413 million, including the value of Pericom equity awards paid out or converted to Diodes equity awards. As a result of the transaction’s close, the common stock of Pericom will no longer be listed for trading on the NASDAQ stock exchange as of the close of market today.

“We are very pleased to complete the acquisition of Pericom, which will be immediately accretive to Diodes’ earnings and also provide enhanced margin expansion opportunities,” stated Dr. Keh-Shew Lu, President and Chief Executive Officer.

“Also notable, this acquisition broadens Diodes’ analog footprint and adds a strong mixed-signal connectivity offering that will drive expanded product content in our target market applications. Pericom also provides an extensive timing product line that complements Diodes’ standard product portfolio.”Dr. Lu also added, “I would like to personally welcome the Pericom employees to the Diodes’ family. Together, we are able to accelerate the attainment of our goal to reach a $1 billion annual revenue run rate with 35 percent gross margin, and I look forward to expanding our global organization and achieving future success.”

Diodes is a global manufacturer and supplier of application specific standard products within the broad discrete, logic and analog semiconductor markets.

Related news

Historic era of consolidation for chip makers

SITRI, a center for accelerating the development and commercialization of “More than Moore” solutions to power the Internet of Things, and Bosch China—through its subsidiary Bosch (China) Investment Ltd.—a global supplier of technology and services, announced today they have signed an agreement to collaborate on the study, development and promotion of solutions and applications for the rapidly growing IoT (Internet of Things) space. The agreement covers IoT applications such as smart home, wearable devices, smart city, Industry 4.0 and robotics.

The agreement facilitates the development of new paths to market for products destined for the rapidly growing China IoT market, for which some analysts have forecasted a CAGR of over 30 percent between now and 2019. It also opens the door to the possible future development of joint demonstration facilities to speed the commercialization ofIoT technologies and products.

“Innovation and applications in the IoT space are developing rapidly,especially in China,” said Dr. Charles Yang, President of SITRI. “Bringing together Bosch’s global technology leadership with SITRI’s unique platform for rapid incubation and commercialization of new IoT technologies will enable a fast start on designs that can be commercialized quickly forthis fast moving market.”

SITRI is emerging as the center for “More than Moore” commercialization and industry development, providing 360-degree solutions for companies and startups pursuing these new technologies, including investment, design, simulation, market engagement and company growth support. SITRI is associated with the Shanghai Institute of Microsystem and Information Technology (SIMIT) and the Chinese Academy of Sciences, and has established strong ties to a broad range of Chinese industry, research and university players. This ecosystem enables these new businesses to grow by quickly taking their innovations from concept to commercialization.

Ambiq Micro appoints new CEO


December 1, 2015

Ambiq Micro, a developer of ultra-low power semiconductor solutions, today announced that Fumihide (Humi) Esakahas joined the firm as Chief Executive Officer. Mr. Esaka takes over from Mike Noonen who was interim CEO since July this year.

Fumihide Esaka has twenty years’ senior management experience in the semiconductor industry and held CEO roles in his last two companies, Nihon Inter Electronics Corp. and, most recently, power conversion specialist, Transphorm Inc. He joined International Rectifier as a Vice President in 1995, where he worked for twelve years, having previously spent six years as a manager at consultancy firm, Accenture.

“This is a most exciting time to be joining Ambiq Micro,” said Mr. Esaka, “the company has started full production of the world’s lowest power microcontroller and it’s already winning designs in leading consumer wearables and other IoT applications. Ambiq’s subthreshold technology is redefining low power in these applications and I look forward to being part of the great team that is driving this transformation in our industry.”

Scott Hanson, Ambiq Micro co-founder and Chief Technology Officer, commented, “Humi brings a wealth of international semiconductor industry experience to Ambiq. He has a deep understanding of power efficiency issues and of their importance to our customers, particularly those that design and manufacture battery-powered devices. This experience is going to be invaluable as we develop Ambiq to be a world leader in ultra-low power semiconductor technology.”

Mr. Esaka was awarded a BA in Electrical Engineering and Computer Science from the University of California, San Diego.

Technavio has added a new market research report on the global discrete semiconductors market, to its semiconductors portfolio. The global discrete semiconductors market is expected to grow at a CAGR of around 5% between 2015 and 2019. APAC dominates the global market, accounting for around 62% of the overall market revenue. The main reason for the high revenue contribution from this region is the high concentration of OEMs and ODMs in the region.

The new industry research report from Technavio discusses in detail the key drivers and trends responsible for the growth of this market and its sub-segments.

“The market vendors are offering various discrete power devices with diverse applications especially to reduce energy wastage. Vendors are increasing the power density, aiming towards energy conservation. More is the power density of discrete semiconductors, netter is the efficiency of these devices which help end-users in saving energy. Moreover, the depletion and rising cost of fossil fuels have made energy conservation a requirement, resulting in the augmented adoption of discrete power semiconductors over the next few years,” said Navin Rajendra, Lead Analyst, Hardware & Semiconductor, Technavio Research.

Automotive segment is the fastest growing segment of the overall discrete semiconductors market. To reduce the dependence on fossil fuels and to reduce environmental hazards, the automotive sector is shifting to hybrid vehicles. Also, these vehicles have more semiconductor content compared to traditional automobiles. This change has raised the demand and requirement for power efficiency fulfilled by the discrete power semiconductors.

The key vendors in the global discrete semiconductors market include Fairchild, Infineon, and NXP. The market is expected to witness a significant push for investments in R&D by the leading market vendors during the forecast period. The main area of vendor focus in the market is toward energy conservation. Many vendors are engrossed in increasing power density, and it is expected to positively impact the implementation of discrete power in newer application areas.

A more detailed analysis is available in the Technavio report, Global Discrete Semiconductors Market 2015-2019.