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Navitas Semiconductor today announced the world’s first Gallium Nitride (GaN) Power ICs, using its proprietary AllGaN™ monolithically-integrated 650V platform. Combining GaN power FETs with GaN logic and drive circuits enables 10x-100x higher switching frequency than existing silicon circuits, making power electronics smaller, lighter and lower cost. A new generation of high frequency, energy efficient converters is being enabled for smartphone and laptop chargers, OLED TVs, LED lighting, solar inverters, wireless charging devices and datacenters.

“Breaking Speed Limits with GaN Power ICs”

“GaN has tremendous potential to displace silicon in the power electronics market given its inherent high-speed, high-efficiency capabilities as a power FET,”

says Dan Kinzer, Navitas CTO & COO.

“Previously, that potential was limited by the lack of equally high performance circuits to drive the GaN FETs quickly and cost effectively. Navitas has solved this remaining challenge to unlock the full potential of the power GaN market. With monolithic integration of GaN drive and logic circuits with GaN power FETs, the industry now has a path to cost-effective, easy-to-use, high-frequency power system designs.”

CEO Gene Sheridan added,

“The last time power electronics experienced a dramatic improvement in density, efficiency and cost was in the late 70s when silicon MOSFETs replaced bipolar transistors, enabling a transition from linear regulators to switching regulators. A 10x improvement in density, 3x reduction in power losses and 3x lower cost resulted a short time thereafter. A similar market disruption is about to occur in which GaN power ICs will enable low-frequency, silicon-based power systems to be replaced by high-frequency GaN with dramatic improvements in density, efficiency and cost. This is an exciting time for the industry.”

About Navitas:

Navitas Semiconductor Inc. is the world’s first and only GaN Power IC company, founded in El Segundo, CA, USA in 2013. Navitas has a strong and growing team of power semiconductor industry experts with a combined 200 years of experience in materials, circuits, applications, systems and marketing, plus a proven record of innovation with over 125 patents among its founders. The proprietary AllGaN™ process design kit monolithically-integrates the highest performance 650V GaN FET and GaN driver capabilities. Navitas GaN Power ICs enable smaller, higher energy efficient and lower cost power for mobile, consumer, enterprise and new energy markets. Over 25 Navitas proprietary patents are granted or pending.

Source

GaN again: good news?

I remember reading a tribune on TI social blog about how much GaN discussions were exhausting these days. The author said that APEC 2015 was hammering with GaN. We have been talking about GaN over and over. And every year it’s the same thing. 2015 Rap Session at APEC concluded once more that “It’s here, it’s coming. It’s good. We need to use it.” The round-table captivated the audience, as usual, but it leads to the same talks and questions with the same kind of people. I understand it becomes exhausting. It’s too much, even for me. I would like Gallium Nitride devices to be out, used everywhere, and that we start talking about something else, like Diamond or carbon nanotubes. I wish we had passed the curve, and we were at the top of it and we were looking at something else.

But we are not there yet. We will still see a lot of GaN, but I hope and I think that we will see different GaN. Let me explain why such a theory.

Why we will see GaN again at APEC this year

We already have device start-ups and bigger companies working on Gallium Nitride devices. We know the pros and cons. We know a lot about the devices themselves. So why would we still talk about that in 2016 at APEC? I wrote recently an article about why we still cannot find GaN in small power supplies (like Zolt and maybe FinSix). GaN devices will irrigate the market in the near future. You find all the analysis, explanations and some roadmap in the GaN Market Analysis report that we’re going to release next month. But there is still a missing thing: conversion systems (and the specialists that come with it).

And Point The Gap’s belief is that this is the next step for GaN. The step where you see big companies trying to use GaN devices, and where you see a few start-ups developing new types of systems. They work on new topologies, architectures, innovative passive components, PCB design or anything needed to make GaN or SiC deliver their best. This new era has started with FinSix  back when it was still On-Chip Power and they were targeting LED power supply business. Now you also have Cambridge Electronics Inc. in Massachusetts, or Nordic Power Converter in Denmark.

You also have companies like Navitas Semiconductor, which, even though they are still in stealth mode and will probably present more during APEC, claim on their single page website that they work on GaN power ICs.

Why is Gallium Nitride good news

We all want a “GaN break ”. But it’s very good news. It means a new era is coming. Now we have companies designing systems using GaN, and innovating at conversion level. Until now, all the power conversion topologies we have developed and invented were aimed at using Silicon. It started with Silicon MOSFET, then IGBT, and Super Junction MOSFET came after that to push further the limits of Silicon. Today, the performance of Silicon has been exploited, and even if we can still improve Si devices, the gain is not as large compared to what it was 10 or 20 years ago. GaN devices are available for sampling and soon for production, and now that system designers have something to work on, I think we will watch them play with it.

Thus we will hear about GaN because we are still expecting system design (and maybe passive components design) to show us what it got.

I bet we will see a few start-up companies going out of stealth mode, and these companies won’t talk about GaN devices. They will blow our mind with GaN based conversion systems. To me, it’s a heck of a good news!

All of this will of course be included in our “GaN devices and applications in power electronics” report, to be released by April of this year.

What else than GaN ?

SiC systems (and a few devices too)

We can definitely expect more Silico-Carbide devices. We have seen and we are seeing more and more systems using SiC MOSFETs. Not much using SiC BJT or other FET. We expect this trend to keep going on. Avogy proved that we can expect GaN and finally see SiC. Maybe it will happen again. PV inverters, UPS, Air conditioning built around full-SiC power modules and discrete devices is to expect this year at APEC.

In addition to that, this is the first year Wolfspeed will attend APEC as « Wolfspeed », grouping ex-Cree Power & RF together with ex-APEI Inc. This would be a good time to announce new projects, joint work or even high-end products. APEI Inc being very good at military or Hi-rel applications.

Power stacks for high-voltage applications are mostly announced during PCIM in May in Nuremberg. I thick we will wait a few more months for these announcements.

Passive components, power stacks or new inverters ?

We will probably have some new stuff on this side. But it’s not easy to define what will be announced in which field. There are some things going-on about digital control. Integration of passive components or Power IC is also fields where we expect to see tome new things announced.

Only time will tell. PointThePower.com will attend. We will be pleased to meet with you. Drop us an e-mail and we will come to you.

Otherwise, stay tuned on the website and you will live APEC as if you traveled, there through our report to come right after the show !

AIXTRON SE, a provider of deposition equipment to the semiconductor industry, has shipped an AIX G5+ C system to French start-up company Exagan, a producer of  gallium nitride (GaN) power switches for electrical converters. The company is a spin-off from Soitec, the SoI (Silicon on insulator) worldwide leader, and CEA-Leti, a European research center focused on micro- and nanotechnologies. Exagan will use Aiwtron’s deposition tool in beginning volume production of gallium nitride on silicon (GaN-on-Si) materials for power-switching devices.

Exagan, in collaboration with its R&D partner CEA-Leti, selected the AIX G5+ C epitaxial deposition tool after evaluating its effectiveness in achieving tight uniformity control and high throughput using Exagan’s proprietary G-Stack™ process technology. This technology is used in creating a unique stack of GaN-based materials that enables the fabrication of Exagan’s G-FET™ transistors. Along with Soitec’s industrial facility and expertise and CEA-Leti’s 200 mm equipment and characterization tools, Aixtron’s equipment adds to Exagan’s supply chain as it ramps up its material production facility in Grenoble.

Fabrice Letertre, COO and Co-Founder of Exagan, comments:

“AIXTRON and our parent company CEA-Leti have enjoyed a long and successful R&D relationship developing GaN-on-Si technology. Now Exagan is partnering with AIXTRON to deliver on our industrial roadmap by using epi to reach our cost milestones. By implementing an efficient GaN-on-Si manufacturing process on 200 mm silicon substrates, we are aligning GaN technology with silicon manufacturing standards. This makes our G-FET products the most cost-efficient wide-bandgap solution for the solar, IT electronics, connectivity and automotive markets.”

[Update 23/02/2016: We had several questions and feedback about this article. We would like to specify its context, hypothesis and boundaries. As specified in the title, this analysis is focusing on a specific application at a given time. We are talking about small laptop chargers for a design made during 2014 with a product released during 2015. This analysis is to change as fast as technologies, manufacturability and product availability will change. We would be happy to have your point of view as well. Please comment if you agree or disagree!]

Our last blog post about GaN in laptop chargers has been widely spread, read and appreciated (even in the French magazine electroniques.biz). On the other side it left some hypothesis, particularly on the type of devices used in these new FinSix Dart and Avogy Zolt laptop chargers. There was no information at the time. Device makers claimed they were suppliers but nothing could confirm it.

Zolt contains a SiC MOSFET from Cree:

Avogy Zolt laptop charger SiC deviceWe do have one Zolt charger at PointThePower.com but we don’t have the lab to tear it down… Our friends from Chipworks did a very well job dismantling and revealing the inside of Zolt.  It was a striking news : Zolt contains an Avogy power device with a Cree1 Silicon Carbide MOSFET (repackaged by Avogy).

We were sure that GaN was the best device for this application, not SiC. And we are still sure about that. We thought that FINsix and Avogy managed to design their laptop charger using Super-Junction MOSFETs and fast smaller MOSFETs. It appears they did not. What option is left then? Silicon Carbide MOSFET.

But if you step back…

There are a few reasons that would lead one to go to SiC rather GaN, for now:

  1. Don’t trust GaN device makers: 600V is not available for production volumes!

Here are two examples to prove my word:

  • I recently read back interviews with two famous GaN makers stating 600V devices will be available by late 2014. We’re in 2016 now and the same makers do not have it yet.
  • I received an e-mail from a reader last year, pointing at a GaN power device announced in January. It disappeared from the catalog in May. We have no news since then.

I’m sure you all have similar examples in mind. So even if the GaN power device market says it’s ready, I want proofs that devices are available for this specific application. We will investigate these proofs in a market report to be released in April this year. We also have GaN devices teardown reports from our LTEC Corp., Our partner.

  1. Silicon Carbide MOSFET is expensive, but available and working

Chipworks Zolt Laptop charger SiC Cree mosfet

Chipworks’ picture of Zolt Laptop charger with SiC MOSFET

Avogy could order SiC MOSFETs and package them as flip-chip SMD. It seems devices switching faster than SJ-MOSFET was something required for their charger design. This is something possible with Silicon carbide if you are willing to pay the price. It’s a bit more difficult using GaN, even if you are in a wealthy company reading to lose some money.

  1. You don’t need the best charger, you need a working tinier charger… fast!

Have you seen FINSix Kickstarter campaign? I don’t blame them, I’m sure they did the work at its best and I know unexpected issues always rise in an engineering project. But similarly to other crowdfunding campaigns, they are late in the delivery of their Dart chargers. That makes backers a bit mad. Avogy managed to deliver less late compared to FINSix. They also designed something quite fast to make it available. This is a winning strategy that required to pick available devices: Silicon Carbide was the preferred solution.

Image capture of Finsix Dart laptop charger on kickstarter

Image capture of Finsix’s campaign on Kickstarter. See www.kickstarter.com

  1. LED and laptop charger market is about size: not efficiency, not lifetime, and not even price!

Yes: not even price. The chargers that we are talking about are expensive. A Zolt is 99 USD, Dart is about the same price. You have to add an extra 20 bucks if you own an Apple laptop. That is more expensive than Apple chargers, which are the most expensive laptop chargers on the market.

So, for a third-party charger this is very expensive. And with these 10 extra bucks you can definitely put a few dollars in a SiC device rather than struggling with a Super-Junction MOSFET. A third option would be to go for GaN, which will probably be cheaper than SiC when it’s available. We did miss that in our analysis of the situation.

There is also no need for a long lifetime as it’s targeting consumer electronics. These products have a maximum life of 3 to 5 years. Why would the charger last more?

Conclusion: SiC vs. GaN leaves SiC as a winner…in 2015

Again it’s all about availability. SiC has been around for 15 years. Gallium Nitride is much newer. So expecting GaN to be ready yet as SiC is still struggling to establish is quite optimistic. GaN will be ready and as of the characteristics we see, we expect it to eat a great amount of the market shares from Super Junction MOSFET. You get can get more information by downloading the sample of our market report: We will establish how, when and where is this market report to be published in April.

GaN-devices

Extract from PointThePower.com Market report to be released April 2016 – (c) Point The Gap

Combine all these reasons together and the best shot if you were designing a small charger using LLC resonant converter topology is either to go for Super Junction MOSFET and optimize cooling like hell… or put one SiC MOSFET die to ease your cooling and optimization design, and be sure you have devices to manufacture you chargers.

I have been working as a market analyst for a few years now, and I start to know about the market, about market players and their habits. There is a common habit in power devices market and start-up world: They are often optimistic.

PointThePower.com tries not to spread too much optimism: because it leads to disappointment.

Notes:

1: Cree has spin-off its RF and Power business units and merged it with APEI Inc, a company they acquired recently. The new entity is called Wolfspeed.

 

Automotive electronics specialist HELLA, in collaboration with GaN Systems, and charging technology researchers at Kettering University’s Advanced Power Electronics Lab have developed a Level-2 electric vehicle (EV) charger prototype with efficiencies exceeding 97% at an unprecedented 2.6 kW/l power density. Prior to this achievement, Level-2 EV chargers reached maximum efficiencies of 94%. Using GaN Systems’ 60 A, 650 V GS66516T switches in an innovative two-stage architecture, the Kettering University research team, led by Associate Professor of Electrical Engineering, Dr. Kevin Bai, were able to increase the wall-to-battery efficiency to more than 3% greater than previously obtained.

HELLA’s Manager of Advanced Engineering, Matt McAmmond, added,

“The results of this collaboration are equally gratifying and commercially important, because they provide HELLA with a path to ultra-compact and lighter EV charger designs. In addition to benefiting HELLA and our customers, this development also has a positive environmental impact, as it represents another step toward the global effort to reduce power consumption.”

Dr. Bai and his team are known for collaborating with companies to help advance their charging technology. Commenting on the importance of this development, Dr. Bai said, “The switching performance we observed with the GaN Systems’ parts was marvelous. Using these devices our power electronics exhibited a power density greater than 2.6 kW/l. This is a significant milestone with important implications for charging electric vehicles, among other charging applications.” Dr. Bai characterized this development as a ‘game changer’ for the EV charging industry.

 

POWDEC has succeeded in making GaN PSJ (Polarized Super Junction) transistors on sapphire substrate having both 1,200 V rating-voltage and the on-resistance of less than 100 mΩ.

Powdec has developed a PSJ (Polarization Super-junction) structure instead of the FP (Field-Plate). The PSJ is so strong against the current collapse that sapphire can be used as substrate. As a result, the device is free from the electric breakdown caused by the substrate. And Powdec succeeded in obtaining up to 6 kV of the breakdown voltage for the device with GaN thickness as thin as 1 μm.

GaN-on-Si devices are applied to the conversion systems only below 600 V rating range. However, the present achievements using the unique PSJ-on-sapphire platform shows that the PSJ devices can enter into the application fields where Si-IGBTs dominate today.

What is Polarized Super Junction?

SJ (Super-junction) is a structure to improve both the conductivity and the breakdown voltage of the Si power-MOS transistor. The drift layer consists of thin p/n stacks while the conventional one consists of a single n-type layer. PSJ (Polarization Super-junction) is a method to implement the SJ effect in the GaN/AlGaN system where the polarization effect functions as SJ.

GaN-on-Silicon versus GaN-on-Sapphire:

Most GaN device makers develop GaN-on-Silicon (or GaN/Si) power devices. Powdec’s 1,200V devices are GaN-on-Sapphire devices. Not using the Silicon and using Sapphire implies intrinsic differences in the device structure and operation.

GaN-on-Si power devices:

GaN power devices today are implemented on Si(111) substrate, which is called “GaN-on-Si” or “GaN/Si”. The thickness of the nitride layers needed for 600V rating devices is generally 5μm or more. The GaN/Si devices are equipped with Field-plates (FP are conductive plates set on the gate to split the steep electric field). FPs are indivisibly needed for the conductive Si substrate to mitigate the current collapses. Current-collapse is another name for the current decreasing phenomenon during the transistor operation. The channel electrons are scattered and deployed around the channel by the strong electric field. These immobile electrons act as the negative bias for the channel resulting in the decrease of the current.

Advantages of GaN-on-Sapphire for Power devices:

Powdec GaN on sapphire gallium nitride power devices PSJ super junctionSapphire substrate is also a common platform for GaN-LED production and the growth runs successively without chamber-cleaning. On the other hand, the growth on Si substrate needs chamber-cleaning prior to the deposition to avoid the unwanted chemical reactions between GaN and Si interface. The chamber-cleaning takes extra time and cost. As a whole, the throughput for GaN PSJ-FET/sapphire growth is roughly ten times larger than that of the GaN FP-HEMT/Si growth.

The thermal conductivity of sapphire, 40 [W/m K], is lower than that of Si, 150 [W/m K]. This problem is solved here by face-downing the die and contacting it on the base substrate, so that the heat can dissipate without going through the sapphire. As a result, the device has operated at as large as 8 amperes of the continuous current mode (CCM) under free standing (without fin) condition.

 

The company HeSaLight has just booked no less than 50,000 power converters at Nordic Power Converters:

Nordic Power Converters is a spin-out company based on several years of technology development at DTU Electrical Engineering. The newly developed power converters that are both smaller and much more durable than traditional power converters are to be used in LED luminaires which HeSaLight manufactures.

The large order and a capital investment of DKK 13m from Seed Capital and 10 other investors means that Nordic Power Converters can now expand the business and hire more employees. Thus the company can really get started with producing tomorrow’s power converters, which could also replace the current big and bulky power converters for PCs for instance. Earlier this year Nordic Power Converters won Danish Tech Challenge – a competition for hardware-based companies and EU’s prize EIT Venture Award.

source

FINsix Corporation , the high-frequency power electronics design start-up, today announced its partnership with Lenovo, the PC manufacturer, to bring Lenovo’s laptops the smallest ever 65W charger option for ThinkPad laptops.

The two companies have collaborated under a joint development agreement, and Lenovo is set to offer the new charger, dubbed the ThinkPad 65W Adapter, as an option for the new ThinkPad X1 Carbon and X1 Yoga. FINsix and Lenovo will be exhibiting the new charger at CES, the global consumer electronics trade show, January 6-9 in Las Vegas.

FINsix is a company Point The Gap featured in its article about Gallium Nitride and consumer power adapters. It developped a laptop adapter using Resonant LLC converter topology to operate at higher frequency of conversion. This high frequency allows smaller passive components and better efficiency. It’s a technology transferred from RF and Military applications. FINsix was initially created on the campus of MIT, with the objective to power LED with their technology. They reoriented their aim to laptop adapters later, as a more accessible market. These technology will be featured in Point The Gap next market report about GaN devices and applications.

An interesting fact about this technology is that today’s FINsix adapters use Infineon Silicon based devices (CoolMOS and OptiMOS, respectively for high voltage and low voltage sides). But it could become and enabler and a first volume produced system to use Gallium Nitride power electronics devices. The topology fits perfectly the high frequency capabilities of GaN devices. It also compensates the youngness of GaN with the relatively short lifetime needed for a laptop charger.

“Lenovo is constantly searching for partners who have disruptive technologies that can add value to our customers,” said Luis Hernandez, vice president and general manager of Lenovo’s ThinkPad Business Unit. “We are working with FINsix because their power conversion technology is a game-changer. It brings a level of portability that we expect will become the standard of the future.”

Vanessa Green, CEO of FINsix, said,

“We are thrilled to partner with the market leader in personal computers. Lenovo has a strong customer base and this collaboration positions us to scale quickly among corporate customers eager to lighten their load when on the go.”

The ThinkPad 65W Micro Adapter is based on the same high-frequency power technology as FINsix’s first product, the Dart, a 65W aftermarket laptop adapter with a 2.1 amp USB port for simultaneously charging phones, tablets, and other devices. The Dart has been featured in a Kickstarter campaign about 18 months ago. Deliveries have been delayed many times and does not seem to have started yet. It was featured at CES in 2014.

 

World-leading nano-electronics research center imec announced today that it is extending its Gallium Nitride-on-Silicon (GaN-on-Si) R&D program, and is now offering joint research on GaN-on-Si 200mm epitaxy and enhancement mode device technology. The extended R&D initiative includes exploration of novel substrates to improve the quality of the epitaxial layers, new isolation modules to increase the level of integration, and the development of advanced vertical devices. Imec welcomes new partners interested in next generation GaN technologies and companies looking for low-volume manufacturing of GaN-on-Si devices to enable the next generation of more efficient and compact power converters.

“Since the program’s launch in July 2009, we have benefited from strong industry engagement, including participation from IDMs, epi-vendors and equipment and material suppliers. This underscores the industrial relevance of our offering,” stated Rudi Cartuyvels, executive vice president of smart systems at imec. “Interested companies are invited to become a partner and actively participate in our program. Imec’s open innovation model allows companies to have early access to next-generation devices and power electronics processes, equipment and technologies and speed up innovation at shared cost.”

GaN technology offers faster switching power devices with higher breakdown voltage and lower on-resistance than silicon, making it an outstanding material for advanced power electronic components. Imec’s R&D program on GaN-on-Si was launched to develop a GaN-on-Si process and bring GaN technology towards industrialization. Building on imec’s excellent track record in GaN epi-layer growth, new device concepts and CMOS device integration, imec has now developed a complete 200mm CMOS-compatible GaN process line. Imec’s GaN-on-Si technology is reaching maturity, and companies can gain access to the platform by joining imec’s GaN-on-Si industrial affiliation program (IIAP). The process line is also open to fabless companies interested in low-volume production of GaN-on-Si devices tailored to their specific needs, through dedicated development projects.

Imec’s portfolio includes three types of buffers optimized for breakdown voltage and low traps-related phenomena (i.e. current dispersion): a step graded AlGaN buffer, a super lattice buffer, and a buffer with low-temperature AlN interlayers. Imec explored side-by-side enhancement mode power devices of the MISHEMT and p-GaN HEMT type, as well as a gate-edge terminated Schottky power diode featuring low reverse leakage and low turn-on voltage.

The latest generation of imec enhancement mode power devices shows a threshold voltage beyond +2V, an on-resistance below 10 ohm mm and output current beyond 450 mA/mm. These devices represents the state of the art of enhancement mode power devices.

In this next phase of the GaN program, imec is focusing on further improving the performance and reliability of its current power devices, while in parallel pushing the boundaries of the technology through innovation in substrate technology, higher levels of integration and exploration of novel device architectures.

source

GaN Systems, the manufacturer of gallium nitride power transistors, announces that its foundry, Taiwan Semiconductor Manufacturing Corporation (TMSC), has expanded the volume production of products based on GaN System’s Island Technology® by 10X in response to demand from consumer and enterprise customers.

GaN Systems has the industry’s broadest and most comprehensive portfolio of GaN power transistors with both 100V and 650V GaN FETs shipping in volume.

The unique combination of TSMC’s gallium nitride process and GaN Systems’ proprietary Island Technology design is further enhanced by GaNPX™ packaging, which delivers high current handling, extremely low inductance and exceptional thermal performance. GaN Systems’ power switching transistors continue to lead the gallium nitride market, providing best-in-class 100V and 650V devices and driving product innovation ranging from thinner TVs to extended range electric vehicles. Sajiv Dalal, VP Business Management at TSMC, comments,

“We are delighted to confirm that our collaboration with GaN Systems has brought the promise of gallium nitride from concept through reliability testing and on to volume production.” Adds Girvan Patterson, GaN Systems’ President,

“GaN has emerged as the power semiconductor solution of choice. Smart mobile devices, slim TVs, games consoles, automotive systems and other mass volume items have been designed with GaN transistors as the enabling power technology, so it is imperative that devices are available in correspondingly large quantities. That is why, after three years of working together, we are so excited to formally announce our collaboration with TSMC.”

Using Island Technology with TSMC’s GaN-on-Silicon manufacturing techniques enabled GaN Systems to deliver the most usable, high performance, normally-off transistor to the market in mid-2014. This has allowed global power system manufacturers in the energy storage, enterprise and consumer markets to design, develop, test and bring to market more powerful, lighter and far smaller new products in their quest to attain competitive edge. To meet customers’ increasing demand for high GaN volumes in 2016, TSMC’s commitment to volume production flow comes at the perfect time.

Check our GaN Market report to know more about GaN Systems and their potential

VisIC Technologies, a technology-leading developer of Gallium Nitride power semiconductors, previously announced the world’s lowest resistance 650V blocking voltage ALL-Switch product family specifying an Rdson as low as 15 mOhm.

VisIC Technologies has now delivered ALL-Switch Evaluation Boards (EB) and samples to leading customers. The EB allows customers to perform extensive testing confirming ALL-Switch’s leadership switching parameters.

The EB includes gate driver and switching control logic based upon commercially available components. ALL-Switch is configured for hard switching on the EB and can switch a 400V load with greater than 30A currents at over 500kHz. (See the attached oscilloscope trace.)

Meeting the highly demanding requirements of power switching with GaN has been the Holy Grail for power conversion research in the last decade. ALL-Switch is a product realization of that research.

VisIC’s technology solves problems that have limited devices from simultaneously achieving step function reductions in conduction and switching losses for power conversion systems that can benefit from high switching speeds.  VisIC’s products easily exceed the performance of competitive products using Silicon, Silicon Carbide or GaN.

VisIC will soon announce soon the details of a Half Bridge reference design.

 

Source

 

Panasonic Corporation today announced that it developed gallium nitride (GaN) diodes that can not only operate at a high current that is four times greater than that tolerated by conventional silicon carbide (SiC) diodes*1, but also operate at low voltages by virtue of their low turn-on voltage. Production of the new diodes was made possible via a newly developed hybrid structure composed of separately embedded structure comprised of a low-voltage unit and a high-current-capable unit, in preparation for high voltage conditions.

Conventional silicon (Si) diodes are limited with regard to reducing switching losses. On the other hand, diodes based on SiC, a compound that is considered as a promising next-generation power semiconductor, as well as GaN, require an increased chip area to achieve high-current operations, thus posing limitations on the reduction of switching losses and size owing to increased operating frequencies.

GaN gallium nitride diode picture from panasonic

The newly produced GaN diodes have achieved simultaneous high-current operations and low threshold voltage, and thus can handle high currents even with a small chip area. The capacitance of the chip can therefore be reduced to achieve lower switching losses, allowing the device to operate at higher frequencies. As a result, use of GaN diodes in the voltage conversion circuits or inverter circuits of automotive or industrial equipment that requires high power can reduce system size due to high frequency operation.

This newly developed product has the following advantages.

・High-current operation: 7.6 kA/cm2 (approximately 4 times*1)
・Lower turn-on voltage: 0.8 V
・Low on-resistance (RonA): 1.3 mΩcm2 (approximately 50% reduction*1)

The diodes were created based on the following technologies.

Hybrid structure of GaN diodes with a trenched p-GaN layer:

We proposed a hybrid GaN diode with a p-type layer in which trenches are formed, and developed a processing technology that can remove a p-type layer on an n-type layer in a selective manner to achieve not only high-current operations and a low turn-on voltage but also a breakdown voltage of 1.6 kV.

Fabrication of Diodes on a low-resistance GaN substrate:

For this development, we used conductive GaN substrates with a low resistance, which have been commercially used in LEDs and semiconductor lasers and are expected to be adopted in power devices in the future, and established the technologies for the epitaxial growth and processing on a GaN substrate before forming diodes. A structure in which currents flow in the vertical direction enables a smaller chip area and lower resistance.

This work was partially supported by the Ministry of the Environment, Government of Japan.

The results of this development were presented at the 2015 International Conference on Solid State Devices and Materials , Sapporo, Japan (September, 2015).

(*1 Compared to an SiC diode with a rated voltage of 1,200 V)