Category Archives: Device Architecture

Nanoelectronics research center imec today announced a strategic partnership on GaN-on-Si (Gallium Nitride-on-Silicon) technology with IQE, a designer and manufacturer of advanced semiconductor wafer products and services.

GaN technology offers faster switching-power devices with higher breakdown voltage and lower on-resistance than silicon, making it an ideal material for advanced power electronic components. The partnership builds on promising results achieved in a recent project, in which imec and IQE collaborated to fabricate GaN power diodes using imec’s proprietary diode architecture and IQE’s high voltage epiwafers.

IQE enters imec’s GaN-on-Si Industrial Affiliation Program that offers joint research and development on GaN-on-Si 200mm epitaxy and enhancement mode device technology to a variety of companies including IDMs, equipment and material suppliers, fabless design houses and packaging companies. The program includes research  on novel substrates to improve the quality of epitaxial layers, new isolation modules to enhance integration levels, and advanced vertical device development. As a GaN-on-Si Program partner, IQE gains access to next-generation epitaxy, devices and power electronics processes, including imec’s complete 200mm CMOS-compatible GaN process line.

“We are delighted to have the opportunity to extend our relationship with imec through the Industrial Affiliation Program,” Wayne Johnson, Head of IQE’s Power Business Unit, said. “The importance of GaN on Si for power devices cannot be understated, particularly as we enter an era of electrically propelled transportation and increasing demands for energy efficient power control systems that require high voltage and high power capabilities.

“IQE’s proven track record in developing and manufacturing GaN based epiwafers, coupled with imec’s unquestionable reputation for world-leading research in nanoelectronics makes for a powerful collaboration in this rapidly growing technology space.”

In its earlier collaborative project, imec worked with IQE to create state-of-the-art GaN power diodes. Imec has applied its proprietary Gated Edge Terminated (GET) Schottky diode device architecture to IQE’s high voltage GaN buffers on 200mm Si substrates. The main challenge on power diodes is to obtain devices that simultaneously show low leakage current and low turn on voltage. Thanks to the GET diode device architecture and to the low buffer leakage current of IQE wafers, the large GaN power diodes (10mm), that were fabricated in imec’s 200mm Si pilot line, showed a low leakage current (up to 650V) and low turn-on voltage. The power Schottky diodes reaches forward and reverse specifications across the full temperature range, spanning from 25˚C till 150˚C with a tight distribution.

“We are excited about this strategic partnership with IQE. Our joint results show that the IQE epiwafers are of excellent quality and are well-aligned to meet the specifications for power Schottky diodes. We look forward to collaborating with IQE to advance our promising results, which demonstrate that our proprietary GET Schottky diode device architecture and process technology can be transferred to external wafers like those provided by IQE,” stated Rudi Cartuyvels, executive vice president smart systems and energy technology at imec. “Our 200mm GaN-on-Si process is available to our program partners and is engineered to fit partner specific product needs.”

TriLumina today announced the appointment of Dan Squiller as Executive Chairman of its Board of Directors. Dan’s experience in the automotive market further strengthens the company’s focus on the high-growth automotive ADAS semiconductor sector.

Dan joins TriLumina with a wealth of experience having served in various senior executive and C-level positions at Scientific Atlanta, St. Bernard Software, Invensys plc, PowerGenix, GT Advanced Technologies, and Verengo Solar. Dan has a broad-base of functional expertise, that includes roles in engineering, operations, product management, sales, marketing, and business development. He has held CEO roles in venture backed early stage companies and co-founded St. Bernard Software, while he has also led billion-dollar, multi-divisional global enterprises. As CEO of PowerGenix, Dan led the shift to a new market segment and achieved technology qualification with Tier1 automotive suppliers in less than 5 years, proving his ability to bring products to the automotive industry effectively. Dan has served on, and chaired, various Boards of Directors and Advisory Boards for industrial companies, business groups, and nonprofits. He currently serves on the boards of Verengo Solar, PowerGenix, and now joins the board of TriLumina.

“I am very excited to join TriLumina, a pioneering start-up developing disruptive VCSEL laser technology that is a true game-changer for the automotive industry,” stated Dan Squiller. “Already sampling their solid-state, scanning laser devices to multiple automotive Tier1s, TriLumina is enabling ADAS solutions spanning from driver monitoring to LiDAR systems for autonomous vehicles.”

“We are pleased to announce the addition of Dan Squiller as Executive Chairman of our Board of Directors,” said Lee Rand, TriLumina Board Member, “The addition of Dan to the Board brings experience in the automotive industry as well as broad leadership skills strengthening the focus on TriLumina’s target markets and supporting our senior leadership team by providing guidance to ensure successful execution on our industry leading laser semiconductor products.”

TriLumina Corp., established in 2010 and headquartered in Albuquerque, New Mexico, is a fabless semiconductor laser technology company that develops, manufactures and integrates among the fastest and most powerful semiconductor laser solutions in the world. TriLumina’s near infrared (NIR) emitters are capable of high power illumination for LiDAR, depth sensing and smart illumination. The company is targeting LiDAR applications in Advance Driver Assistance Systems (ADAS) and Driver Monitoring Systems (DMS) for cockpit applications in the automotive market, as well as, depth sensing and gesture control for the industrial robotics, commercial and consumer electronics markets.

STMicroelectronics announced advanced high-efficiency power semiconductors for Hybrid and Electric Vehicles (EVs) with a timetable for qualification to the automotive quality standard AEC-Q101.

In EVs and hybrids, where better electrical efficiency means greater mileage, ST’s latest silicon-carbide (SiC) technology enables auto makers to create vehicles that travel further, recharge faster, and fit better into owners’ lives. A leader in silicon carbide, ST is among the first to present new-generation rectifiers and MOSFETs for high-voltage power modules and discrete solutions addressing all the vehicle’s main electrical blocks. These include the traction inverter, on-board battery charger, and auxiliary DC-DC converter.

Today’s power modules typically rely on standard silicon diodes and Insulated Gate Bipolar Transistors (IGBTs). Silicon carbide is a newer, wide-bandgap technology that allows smaller device geometries capable of operating well above the 400V range of today’s electric and hybrid drivetrains. The smaller SiC diode and transistor structures present lower internal resistance and respond more quickly than standard silicon devices, which minimize energy losses and allow associated components to be smaller, saving even more size and weight.

“Major carmakers and automotive Tier-1s are now committing to silicon-carbide technology for future product development to leverage its higher aggregate efficiency compared to standard silicon in a wide range of operating scenarios,” said Mario Aleo, Group Vice President and General Manager, Power Transistor Division, STMicroelectronics. “Our SiC devices have demonstrated superior performance and reached an advanced stage of qualification as we support customers preparing to launch new products in the 2017 timeframe.”

ST has been among the first companies to produce silicon-carbide high-voltage MOSFETs, with its first 1200V SiC MOSFET introduced back in 2014, achieving industry-leading 200degreesC rating for more efficient and simplified designs.

The Company is using the industry’s most advanced processes to fabricate SiC MOSFETs and diodes on 4-inch wafers. In order to drive down the manufacturing costs, improve the quality, and deliver the large volumes demanded by the auto industry, ST is scaling up its production of SiC MOSFETs and diodes to 6-inch wafers, and is on schedule to complete both conversions by the end of 2016.

ST has already qualified its 650V SiC diodes to AEC-Q101, and will complete qualification of the latest 650V SiC MOSFETs and 1200V SiC diodes in early 2017. The qualification of the new-generation 1200V SiC MOSFETs will be completed by the end of 2017.

The STPSC20065WY 650V SiC diode is in full production now in DO-247. The range also includes lower current ratings and smaller form-factor TO-220 package options. The STPSC10H12D 1200V SiC diode is sampling now to lead customers in the TO-220AC package and goes to production this month, with volume production of the automotive-grade version planned for Q4 2016. Multiple current ratings from 6A to 20A and packaging options will also be available.

The SCTW100N65G2AG 650V SiC MOSFET is sampling now to lead customers in the HiP247 package. It will ramp up in volumes in H1 2017. To enable more compact designs, a 650V SiC MOSFET in the surface-mount H2PAK will also be qualified to AEC-Q101 in H1 2017.

IC Insights will release its May Update to the 2016 McClean Report later this month.  This Update includes a discussion of the 1Q16 semiconductor industry market results, an update of the capital spending forecast by company, a review of the IC market by electronic system type, and a look at the top-25 1Q16 semiconductor suppliers (the top 20 1Q16 semiconductor suppliers are covered in this research bulletin).

The top-20 worldwide semiconductor (IC and O S D—optoelectronic, sensor, and discrete) sales ranking for 1Q16 is shown in Figure 1.  It includes eight suppliers headquartered in the U.S., three in Japan, three in Taiwan, three in Europe, two in South Korea, and one in Singapore, a relatively broad representation of geographic regions.

The top-20 ranking includes three pure-play foundries (TSMC, GlobalFoundries, and UMC) and six fabless companies. If the three pure-play foundries were excluded from the top-20 ranking, U.S.-based IDM ON Semiconductor ($817 million), China-based fabless supplier HiSilicon ($810 million), and Japan-based IDM Sharp ($800 million) would have been ranked in the 18th, 19th, and 20th positions, respectively.

IC Insights includes foundries in the top-20 semiconductor supplier ranking since it has always viewed the ranking as a top supplier list, not a marketshare ranking, and realizes that in some cases the semiconductor sales are double counted.  With many of our clients being vendors to the semiconductor industry (supplying equipment, chemicals, gases, etc.), excluding large IC manufacturers like the foundries would leave significant “holes” in the list of top semiconductor suppliers.  As shown in the listing, the foundries and fabless companies are identified.  In the April Update to The McClean Report, marketshare rankings of IC suppliers by product type were presented and foundries were excluded from these listings.

Overall, the top-20 list shown in Figure 1 is provided as a guideline to identify which companies are the leading semiconductor suppliers, whether they are IDMs, fabless companies, or foundries.

Figure 1

Figure 1

In total, the top-20 semiconductor companies’ sales declined by 6% in 1Q16/1Q15, one point less than the total worldwide semiconductor industry decline of 7%.  Although, in total, the top-20 1Q16 semiconductor companies registered a moderate 6% drop, there were seven companies that displayed a double-digit 1Q16/1Q15 decline and three that registered a ≥25% fall (with memory giants Micron and SK Hynix posting the worst results).  Half of the top-20 companies had sales of at least $2.0 billion in 1Q16.  As shown, it took $832 million in quarterly sales just to make it into the 1Q16 top-20 semiconductor supplier list.

There was one new entrant into the top-20 ranking in 1Q16—U.S.-based fabless supplier AMD.  AMD had a particularly rough 1Q16 and saw its sales drop 19% year-over-year to $832 million, which was about half the $1,589 million in sales the company logged just over two years ago in 4Q13.  Although AMD did not have a good 1Q16, Japan-based Sharp, the only company that fell from the top-20 ranking, faired even worse with its 1Q16/1Q15 sales plunging by 30%!

In order to allow for more useful year-over-year comparisons, acquired/merged semiconductor company sales results were combined for both 1Q15 and 1Q16, regardless of when the acquisition or merger occurred.  For example, although Intel’s acquisition of Altera did not close until late December of 2015, Altera’s 1Q15 sales ($435 million) were added to Intel’s 1Q15 sales ($11,632 million) to come up with the $12,067 million shown in Figure 1 for Intel’s 1Q15 sales.  The same method was used to calculate the 1Q15 sales for Broadcom Ltd. (Avago/Broadcom), NXP (NXP/Freescale), and GlobalFoundries (GlobalFoundries/IBM).

Apple is an anomaly in the top-20 ranking with regards to major semiconductor suppliers. The company designs and uses its processors only in its own products—there are no sales of the company’s MPUs to other system makers. Apple’s custom ARM-based SoC processors had a “sales value” of $1,390 million in 1Q16, up 10% from $1,260 million in 1Q15.  Apple’s MPUs have been used in 13 iPhone handset designs since 2007 and a dozen iPad tablet models since 2010 as well as in iPod portable media players, smartwatches, and Apple TV units.  Apple’s custom processors—such as the 64-bit A9 used in iPhone 6s and 6s Plus handsets introduced in September 2015 and the new iPhone 6SE launched in March 2016—are made by pure-play foundry TSMC and IDM foundry Samsung.

Intel remained firmly in control of the number one spot in 1Q16.  In fact, it increased its lead over Samsung’s semiconductor sales from 29% in 1Q15 to 40% in 1Q16.  The biggest moves in the ranking were made by the new Broadcom Ltd. (Avago/Broadcom) and Nvidia, each of which jumped up three positions in 1Q16 as compared to 1Q15.

As would be expected, given the possible acquisitions and mergers that could/will occur this year (e.g., Microchip/Atmel), as well as any new ones that may develop, the top-20 semiconductor ranking is likely to undergo a significant amount of upheaval over the next few years as the semiconductor industry continues along its path to maturity.

Samsung Electronics Co. Ltd. today recognized five of the best and brightest computer science and engineering students in the U.S. as it announced the inaugural class of the Samsung PhD Fellowship. Each student will receive a Fellowship award of $50,000 as well as mentorship to support their ground-breaking research.

The new PhD Fellowship program rewards those who dare to innovate. Jointly sponsored by Samsung Semiconductor and the Samsung Strategy and Innovation Center (SSIC), the program recognizes outstanding Ph.D. students working in five areas: Software and Memory System Solutions for Data Centers; Low-Power CPU and System IP Architecture and Designs; Advanced Semiconductor Devices, Materials and Simulation; Internet of Things; and Smart Machines.

Samsung launched the Fellowship program with a call for partner universities to nominate outstanding students working on the above topics. Twelve of the best-qualified nominees were selected as Finalists and invited to showcase events at the new headquarters in Silicon Valley or at the Samsung Austin R&D Center. Each student Finalist presented his or her research proposal to an audience of Samsung engineers, Lab directors, and innovation leaders and met many of them for interviews as well. Following these events, the five Fellows were selected from this terrific group.

Each Fellow will be connected to an engineer from one of the Samsung Semiconductor or SSIC Labs in Silicon Valley or Austin. This mentor will provide an industry perspective on their research and will invite the student to join Samsung for an internship.

“We are thrilled to be supporting these outstanding students through our Fellowship program. Samsung strives to be a leader in the creation of new technology, and a great way to do that is by supporting basic research and PhD training,” said Stefan Heuser, VP of Operations and Innovation for SSIC. “We were very impressed by the students nominated by the universities—all of them have made an impact in key areas of research. The Finalists were an even stronger group, and we are confident that they will become leaders in their fields. But the five Fellows are truly exceptional, and we look forward to working with them in the coming year. We thank the universities and all of the student nominees for their efforts and for their interest in our program.”

Following are the five Samsung PhD Fellows for 2016-2017:

  • Dinesh Jayaraman, “Embodied Learning for Visual Recognition”
    Nominating professor: Kristen Grauman, University of Texas at Austin
  • Jiajun Wu, “Computational Perception of Physical Object Properties”
    Nominating professors: William Freeman and Joshua Tenenbaum, MIT
  • Joy Arulraj, “Rethinking Database Systems for Next-Generation Memory Technologies and Real-Time Analytics”
    Nominating professor: Andy Pavlo, Carnegie Mellon University
  • Niranjini Rajagopal, “Sensor Fusion and Automatic Infrastructure Mapping for Indoor Localization Systems”
    Nominating professors: Anthony Rowe and Bruno Sinopoli, Carnegie Mellon University
  • Wooseok Lee, “Exploring Future Mobile Heterogeneous Multicore System Architectures”
    Nominating professors: Lizy John and Andreas Gerstlauer, University of Texas at Austin

Nominations for next year’s PhD Fellowship program will open in September 2016. Additional information about the Fellowship program can be found at: http://www.samsung.com/us/labs/fellowship/index.html

By Art Paredes, SEMI

Nearly 5,000 visitors and exhibitor personnel assembled in Penang last month for SEMICON Southeast Asia 2016, the largest trade show for the electronics manufacturing supply chain in the region. This year’s event featured over 80 speakers and 200 companies participating, with exhibiting companies from countries spanning the globe.

In its second year in Penang, SEMICON Southeast Asia serves as the primary platform for semiconductor equipment and materials manufacturing, assembly, test & packaging services, electronic manufacturing services (EMS), smart manufacturing technologies, and industrial IoT applications.

“With more programs and speakers this year – and the increased number of exhibiting companies, we are extremely pleased with the continued growth of SEMICON Southeast Asia,” stated Kai Fai Ng, president of SEMI Southeast Asia. Mr. Ng also stated: “the support and leadership of our Regional Advisory Board, chaired by Mr. KC Ang, senior vice president and GM of GLOBALFOUNDRIES – and the Southeast Asia Technical Committees, chaired by Mr. Nelson Wong, VP of the Ball Bonder Business Unit at Kulicke & Soffa, was greatly appreciated – and a key reason for our success.”

In addition to the sold-out exhibition hall, SEMICON Southeast Asia presented more than 90 targeted sessions and panel discussions. Key programs included the Market Trends Briefing, Supply Chain in High Tech Industry Forum, Advanced Packaging Forum, Technology Innovation Forum, Product & System Testing Forum, Sustainable Manufacturing Forum, Electrical Fault Isolation Tutorial, LED Technology Forum, and the IC Failure Analysis & Yield Productivity Forum.

Each program featured excellent speakers from the extended electronics supply chain, including KL Bock, VP of Manufacturing at SanDisk; John Galang, SEA regional director, Global Manufacturing Operations at Cisco Systems; Yohei “Fred” Sato, director ATS Marketing at TEL; Mr. CS Tan, Group VP & GM at ST Microelectronics; Ms. Fariba Abhari, director of Marketing IoT/MEMS Business Group at Lam Research; Dr. Poh Leng Eu, head of Package Innovation at NXP; Dr. Shang Yang, senior R&D Applications engineer at Advantest; Mr. Arvind Sundarrajan, head of Asia Product Development Centre at Applied Materials and; Mr. Dennis Wee, Product Engineering manager at Broadcom, to name a few.

Sold out exhibition hall

SEMICON Southeast Asia’s exhibition grew an additional 12 percent over 2015. The show floor featured many leading equipment and materials manufacturers, assembly, test & packaging providers, electronic manufacturing service (EMS) providers, and numerous suppliers from the electronics supply chain. A sample of exhibiting companies included: Advantest, DAS, DISCO, Faeth, GE Sensing & Inspection, Hermes-Epiteck, Hitachi Power Solutions, Hiwin, Lam Research, SCREEN, Surplus Global, Tokyo Electron, ULVAC, UST Technology, Yaskawa, and ZMC Technologies, to name a few. Key pavilions from Singapore, Silicon Saxony and the Malaysia Investment & Development Agency (MIDA) were also present on the show floor.

Over 200 industry leaders gathered on the summit of Penang Hill (also known as Bukit Bendera) for the annual SEMICON Southeast Asia networking event, hosted by InvestPenang. Lush gardens, live music, cooler temperatures, and fantastic views of Georgetown and mainland Penang provided the ideal backdrop for an entertaining and memorable evening.

“SEMICON Southeast Asia plays a vital role for the local economy and the continued growth of the electrical & electronics industry in Penang and throughout Malaysia,” stated Ms. Lee Lian Loo, GM of InvestPenang. “We are pleased to partner with SEMI for this outstanding trade show.”

Southeast Asia Remains a Key Market

Southeast Asia continues to play a vital role in the global IC industry and accounts for more than 27 percent of the world’s assembly, packaging and test production – and is the single largest market for packaging materials and equipment.

Dan Tracy, senior director, Industry Research & Statistics at SEMI, speaking at the Market Trends Briefing, provided a summary of year-to-date trends and a comprehensive market outlook for the global semiconductor equipment and materials market. Tracy emphasized the importance and relevance of the Southeast Asia market and the expected continuing growth in the materials and equipment sectors. According to the SEMI Materials Market Data Subscription (April 2016), Southeast Asia will account for approximately 24 percent of the total semiconductor packaging materials markets and about 14 percent of the regional fab materials market.

For more information regarding SEMICON Southeast Asia, please visit www.semiconsea.org or contact Ms. Shannen Koh at [email protected]. For additional information on SEMI’s global expositions, please visit www.semiexpos.org or contact Mr. Art Paredes @ [email protected].

FlexTech, a SEMI Strategic Association Partner, today announced the formal completion of three flexible hybrid electronics (FHE) R&D projects under its U.S. Army Research Laboratory  (ARL) technology investment agreement.  The completed projects are with ENrG for a flexible ceramic substrate; nScrypt and NovaCentrix for a next-generation three-dimensional (3D) printing tool for creating complex and functional objects; and PARC, a Xerox company, for a flexible sensor platform. Projects ranged from 12-18 months and were managed by a member of the FlexTech Technical Council, which is a team of experts in flexible, hybrid and printed electronics technologies.

  • ENrG, located in Buffalo, New York, completed a 15 month project to develop a high-yield process to create a 20 micron thick, flexible ceramic substrate capable of retaining its integrity when drilled, cut, rolled and processed at high temperatures. During the project, ENrG developed processes to print thin-film lithium batteries, circuits, application of copper cladding and other metallization with excellent performance characteristics. The project, valued at $570,000 total, was 56% cost shared by the company.
  • nScrypt, based in Orlando, Florida, in partnership with NovaCentrix of Austin, Texas, developed a 3D printer for rapid prototyping of new electronic devices. The total award of $1,291,000 was cost-shared by nScrpyt, NovaCentrix and FlexTech and it was completed over a 16-month period. The new tool additively builds integrated hybrid circuits on 3D surfaces, as well as devices on flexible, low temperature, and rigid planar substrates. It integrates processing of three previously-separate tools. The first tool has been installed at ARL. Commercial tools are available from nScrypt.
  • PARC, a Xerox Company, Palo Alto, California, developed a passively powered, digitally-fabricated, communication-enabled, flexible sensor platform that is easily customizable to multiple sensor types. The project addressed the availability of an end-to-end system design that can be manufactured in large quantities with digital printing for smart tag or wearable applications. In its final report, the PARC researchers noted several key areas where additional development would be helpful, including components designed specifically to be compatible with flexible, printed sensor systems. Total cost was $409,000 and shared equally between PARC and FlexTech.

“Each of these projects, chosen and supported by the Technical Council, moves the needle on learning how to fabricate electronics on flexible substrates,” stated Michael Ciesinski, president of FlexTech. “Especially impressive is the teaming on the projects, which helps build out the FHE supply chain.”

FlexTech, a SEMI Strategic Association Partner, is focused on growth, profitability, and success throughout the manufacturing and distribution chain of flexible hybrid electronics, by developing solutions for advancing these technologies from R&D to commercialization. Learn more at www.nscrypt.com, www.novacentrix.com, www.enrg-inc.com, www.parc.com

For more information, visit www.semi.org

Standard solutions and devices are compared to a 60 V MOSFET with monolithic Schottky diode as evaluated in SMPS and motor control environments.

BY FILIPPO SCRIMIZZI and FILADELFO FUSILLO, STMicroelectronics, Stradale Primosole 50, Catania, Italy

On synchronous rectification and in bridge configuration, RDSon and Qg are not the only requirements for power MOSFETs. In fact, the dynamic behavior of intrinsic body-drain diode also plays an important role in the overall MOSFET performances. The forward voltage drop (VF,diode) of a body-drain diode impacts the device losses during freewheeling periods (when the device is in off-state and the current flows from source to drain through the intrinsic diode); the reverse recovery charge (Qrr) affects not only the device losses during the reverse recovery process but also the switching behavior, as the voltage spike across the MOSFET increases with Qrr. So, low VFD and Qrr diodes, like Schottky, can improve overall device performance, especially when mounted in bridge topologies or used as synchronous rectifiers—especially at high switching frequency and for long diode conduction times. In this article, we compare standard solutions and devices to a 60 V MOSFET with monolithic Schottky diode as evaluated in SMPS and motor control environments.

Intrinsic MOSFET body-drain diode and Schottky features

In FIGURE 1, the typical symbol for an N-channel Power MOSFET is depicted. The intrinsic body-drain diode is formed by the p-body and n–drift regions and is shown in parallel to the MOSFET channel.

Screen Shot 2016-05-11 at 12.08.52 PM

 

Once a Power MOSFET is selected, the integral body diode is fixed by silicon characteristic and device design. As the intrinsic body diode is paralleled to the device channel, it is important to analyze its static and dynamic behavior, especially in applications where the body diode conducts. So, maximum blocking voltage and forward current have to be considered in reverse and forward bias, while, when the diode turns-off after conducting, it is important to investigate the reverse recovery process (FIGURE 2). When the diode goes from forward to reverse bias, the current doesn’t reduce to zero immediately, as the charge stored during on-state has to be removed. So, at t = t0, the diode commutation process starts, and the current reduces with a constant and slope (-a), fixed only by the external inductances and the supply voltage. The diode is forward biased until t1, while from t1 to t2, the voltage drop across the diode increases, reaching the supply voltage with the maximum reverse current at t=t2. The time interval (t3-t0) is defined as reverse recovery time (trr) while the area between negative current and zero line is the reverse recovery charge (Qrr).The current slope during tB is linked mainly to device design and silicon characteristics.

Screen Shot 2016-05-11 at 12.08.59 PM

The classification of soft and snap recovery is based on the softness factor: Screen Shot 2016-05-11 at 12.09.58 PMthis parameter can be important in many applications. The higher the softness factor, the softer the recovery. In fact, if tB region is very short, the effect of quick current change with the circuit intrinsic inductances can produce undesired voltage overshoot and ringing. This voltage spike could exceed the device breakdown voltage: moreover, EMI performances worsen. As shown in Fig. 2, during diode recovery, high currents and reverse voltage can produce instantaneous power dissipation, reducing the system efficiency. Moreover, in bridge topologies, the maximum reverse recovery current of a Low Side device adds to the High Side current, increasing its power dissipation up to maximum ratings. In switching applications, like bridge topologies, buck converters, or synchronous rectification, body diodes are used as freewheeling elements. In these cases, reverse recovery charge (Qrr) reduction can help maximize system efficiency and limit possible voltage spike and switching noise at turn-off. One strategy to reach this target to integrate a Schottky diode in the MOSFET structure. A Schottky diode is realized by an electrical contact between a thin film of metal and a semiconductor region. As the current is mainly due to majority carriers, Schottky diode has lower stored charge, and consequently, it can be switched from forward to reverse bias faster than a silicon device. An additional advantage is its lower forward voltage drop (≈0.3 V) than Si diodes, meaning that a Schottky diode has lower losses during the on state.

Embedding the Schottky diode in a 60V power MOSFET is the right device choice when Qrr and VF,diode have to be optimized to enhance the overall system performance. In FIGURE 3, the main electrical parameters of standard and integrated Schottky devices (same BVDSS and die size) are reported.

Screen Shot 2016-05-11 at 12.09.06 PM

Benefits of Mono Schottky in a power management environment

In a synchronous buck converter (FIGURE 4), a power MOSFET with integrated Schottky diode can be mounted as a Low Side device (S2) to enhance the overall converter performance.

Screen Shot 2016-05-11 at 12.09.13 PM

In fact, Low Side body diode conduction losses (Pdiode,cond) and reverse recovery losses (PQrr) are strictly related to the diode forward voltage drop (VF,diode) and its reverse recovery charge (Qrr):

Screen Shot 2016-05-11 at 12.09.20 PM

As shown in (1) and (2), these losses increase with the switching frequency, the converter input voltage, and the output current. Moreover, the dead time, when both FETs are off and the current flows in the Low Side body diode, seriously affects the diode conduction losses: with long dead times, a low diode forward voltage drop helps to minimize its conduction losses, therefore increasing the efficiency. In FIGURE 5, the efficiency in a 60W, 48V – 12V, 250 kHz synchronous buck converter is depicted.

Screen Shot 2016-05-11 at 12.09.26 PM

Now, considering isolated power converters’ environment, when the output power increases and the dead time values are high, the right secondary side synchronous rectifier should have not only RDSon as low as possible to reduce conduction losses, but also optimized body diode behavior (in terms of Qrr and VF,diode) in order to reduce diode losses (as reported in (1) and (2)) and to minimize possible voltage spikes during turn-off transient. The 60V standard MOSFET and one with Schottky integrated devices are compared in a 500W digital power supply, formed by two power stages: power factor corrector and an LLC with synchronous rectification. The maximum output current is 42 A, while the switching frequency at full load is 80 kHz, and the dead time is 1μs. The efficiency curves are compared in FIGURE 6.

Screen Shot 2016-05-11 at 12.09.32 PM

In both topologies, the 60 V plus Schottky device shows higher efficiency in the entire current range, an improvement in overall system performance.

Switching behavior improvement in bridge topologies

In bridge topologies, reverse recovery process occurs at the end of the freewheeling period of the Low Side device (Q2 in FIGURE 7), before the High Side (Q1 in Fig. 7) starts conducting. The resulting recovery current adds to the High Side current (as previously explained). Together with the extra-current on the High Side device, the Low Side reverse recovery and its commutation from Vds ≈ 0 V to Vdc can produce spurious bouncing on the Low Side gate- source voltage, due to induced charging of Low Side Ciss (input capacitance) via Crss (Miller capacitance).

Screen Shot 2016-05-11 at 12.09.38 PM

As a consequence, the induced voltage on Q2 gate could turn-on the device, worsening system robustness and efficiency. A Low Side device, in bridge configuration, should have soft commutation, without dangerous voltage spikes and high frequency ringing across drain and source. This switching behavior can be achieved using power MOSFETs with integrated Schottky diode as Low Side devices. In fact, the lower reverse recovery charge (Qrr) has a direct impact on the overshoot value. In fact, the higher the Qrr, the higher the overshoot. Lower values for Vds overshoot and ringing reduce the spurious voltage bouncing on the Low Side gate, limiting the potential risk for a shoot-through event. Furthermore, soft recovery enhances overall EMI performances, as the switching noise is reduced. In FIGURE 8 are shown the High Side turn-on waveforms for standard and embedded Schottky devices; purple trace (left graph) and green trace (right graph) are Low Side gate-source voltages. The device with Schottky diode shows a strong reduction of Low Side spurious bouncing.

Screen Shot 2016-05-11 at 12.09.47 PM

Summary

In many applications (synchronous rectification for indus- trial and telecom SMPS, DC-AC inverter, motor drives), choosing the right MOSFET means not only considering RDSon and Qg but also evaluating the static and dynamic behavior of the intrinsic body-drain diode. A 60V “F7” power MOSFET with integrated Schottky diode ensures optimized performances in efficiency and commutation when a soft reverse recovery with low Qrr is required. Furthermore, the low VF,diode value achieves higher efficiency when long freewheeling periods or dead-times are present in the application.

References

1. “Fundamental of Power Semiconductor Devices”, B.J.Baliga – 2008, Springer Science

Maxim Integrated Products, Inc. today announced the retirement of Kip Hagopian as the Company’s Chairman of the Board. William (Bill) P. Sullivan, currently a member of Maxim’s Board, will assume the Board Chair position, effective immediately. Mr. Hagopian will continue to serve on the Board, in a non-Chair director capacity, until the end of Maxim’s 2016 fiscal year, June 25, 2016. The Board of Directors voted to give Mr. Hagopian the honorary title of Chairman Emeritus.

Mr. Hagopian, who was a founding investor in Maxim in his capacity as a General Partner and Founder of private equity and venture capital firm, Brentwood Associates, served as a member of Maxim’s Board of Directors during two separate time periods: first, from Maxim’s founding in 1983 until 1989, shortly after the Company’s 1988 initial public offering; then, from 1997 to the present. He has held the position of Chairman since 2007.

“We thank Kip for his leadership, dedication, and decades of commitment to Maxim, and wish him the best in his retirement. Kip consistently provided key strategic advice and excellent board leadership throughout his tenure as Chairman, during which we could always count on him to challenge the management team to make Maxim a better company,” said Tunc Doluca, Maxim Integrated’s President and Chief Executive Officer.

Reflecting on his retirement, Mr. Hagopian said, “This is a bittersweet moment in my career. I am excited by what my future may hold, both in business and philanthropy. But I am also sad to be leaving a company that I have served and loved for half my business life. I will particularly miss working with Maxim’s extraordinary CEO, Tunc Doluca and the superb management team he leads, as well as my very talented colleagues and good friends on the Maxim Board.”

William Sullivan, who will assume the position of Chairman, is a veteran of more than two decades at Hewlett-Packard (HP), and from 2005 to 2015, served as Chief Executive Officer of Agilent Technologies, a global provider of scientific instruments, software, services and consumables in life sciences, diagnostics, and applied chemical markets, after its spin-out from HP. Prior to that, he was Executive Vice President and Chief Operating Officer of Agilent from 2002 to 2005 and Senior Vice President and General Manager of Agilent’s Semiconductor Products Group from 1999 to 2002. Mr. Sullivan spent the first 23 years of his career at HP in a series of management positions of increasing responsibility, mainly in the semiconductor group.

“As a member of the search committee, I was active in recruiting Bill Sullivan to the Maxim Board and have come to know him as an exceptionally qualified and highly respected technology executive. Given his extensive experience as a veteran of the semiconductor industry, he is a natural fit for the role of Chairman of Maxim’s Board,” said Mr. Hagopian.

“I have known Bill for several years and am very much looking forward to working with him,” added Tunc Doluca. “Enhanced customer engagement and insight are important elements of our focus on growing revenue, and Bill’s counsel and oversight will add greatly to meeting our strategic objectives.”

Worldwide semiconductor capital spending is projected to decline 2 percent in 2016, to $62.8 billion, according to Gartner, Inc. (see Table 1). This is up from the estimated 4.7 percent decline in Gartner’s previous quarterly forecast.

“While the first quarter 2016 forecast has improved from a projected decline of 4.7 percent in the previous quarter’s forecast, the 2 percent decline in the market for 2016 is still bleak,” said David Christensen, senior research analyst at Gartner. “Excess inventory and weak demand for PCs, tablets, and mobile products continue to plague the semiconductor industry, resulting in a slow growth rate that began in late 2015 and is continuing into 2016.”

Table 1

Worldwide Semiconductor Capital Spending and Equipment Spending Forecast, 2015-2018 (Millions of Dollars)

2015

2016

2017

2018

Semiconductor Capital Spending ($M)

64,062.9

62,795.3

65,528.5

70,009.5

Growth (%)

-0.8

-2.0

4.4

6.8

Wafer-Level Manufacturing Equipment ($M)

33,248.1

32,642.0

34,897.6

37,641.1

Growth (%)

-1.1

-1.8

6.9

7.9

Wafer Fab Equipment ($M)

31,485.4

30,841.9

32,930.3

35,443.4

Growth (%)

-1.3

-2.0

6.8

7.6

Wafer-Level Packaging and Assembly Equipment ($M)

1,762.7

1,800.2

1,967.3

2,197.7

Growth (%)

4.1

2.1

9.3

11.7

Source: Gartner (May 2016)

“The slowdown in the devices market has driven semiconductor producers to be conservative with their capital spending plans,” said Mr. Christensen. “This year, leading semiconductor manufacturers are responding to anticipated weak demand from semiconductors and preparing for new growth in leading-edge technologies in 2017.”

In addition, the aggressive pursuit of semiconductor manufacturing capability by the Chinese government is an issue that cannot be ignored by the semiconductor manufacturing industry. In the last year, there has been consolidation and merger and acquisition (M&A) activity with specific offers from various Chinese-based entities, indicating the aggressiveness of the Chinese. This will dramatically affect the competitive landscape of global semiconductor manufacturing in the next few years, as China is now a major market for semiconductor usage and manufacturing.

Looking forward, the market is expected to return to growth in 2017. Increased demand for 10 nanometer (nm) and 3D NAND process development in memory and logic/foundry will drive overall spending to grow 4.4 percent in 2017.

This research is produced by Gartner’s Semiconductor Manufacturing program. This research program, which is part of the overall semiconductor research group, provides a comprehensive view of the entire semiconductor industry, from manufacturing to device and application market trends. Additional analysis on the outlook for the semiconductor market can be found at “Forecast Analysis: Capital Spending and Semiconductor Manufacturing Equipment, Worldwide, 1Q16.”