Mature Wide Band Gap Semiconductors in Systems: A Tech Review of Presentations at PCIM


Bodo Arlt, Publishing Editor at Bodo's Power Systems

Bodo Arlt

We are seeing more and more applications that utilize SiC and GaN semiconductors. The benefits are mounting to use them to minimize losses in systems.

The discussions regarding SiC and GaN have been ongoing for years and we have reached a point where volume production is starting and applications have a new design approach for systems. Following our yearly tradition, we had discussions with leading representatives from the industry at PCIM Europe. Here are reflections and overviews showing what has been achieved in both SiC and GaN.

 

SiC Presentations

Below, I have summarized the key messages from each of the presenters for SiC.

ROHM

ROHM has a fully integrated supply chain using SiCristal as their in-house wafer source. The target is 30 percent market share. The next step for growth is the plan for the new ROHM Apollo fab in Fukuoka, Japan. This fab should start production in 2020. Construction will start in February 2019. The building will have 11000 m² of space for production.

 

Infineon

Infineon stated that the SiC Schottky diode is key for high efficiency in charging systems and 1200V SiC MOSFET for a reduced part count, system simplification and power density in a charger system for electromobility. A SiC MOSFET can reduce system size and cost. The benefits are shown as follow: Higher switching frequency means smaller transformers. Same power in smaller box size results in system size and weight reduction.

 

Mitsubishi 

Mitsubishi Silicon Body Diode (SBD)-embedded SiC MOSFET technology can realize smaller chip area than conventional design (MOSFET and external SBD) by embedding SBD into each unit cell of the SiC MOSFET. As a result compact SiC module design can be implemented by Mitsubishi technology.

 

UnitedSiC

UnitedSiC presented The Cascode Advantages:

Ease of use: Vgsmax=+/-25V; Vth=5V typ. The device can operate from 0 to 12V, or any desired gate voltage range and is inter-operable with Si MOSFET, IGBTs, and SiC MOSFETs Robustness features:

  • The gate ESD protection is 3.5KV and 100% UIS tested.
  • The device is able to handle repetitive avalanche and short circuit events. ( AEC-Q101)
  • Performance features: JFET is lowest RdsA SiC Switch, TJMAX=175C, VTH >3V at 175C
  • Enhanced thermal – low RthJC, Low RDSON and EON/EOFF and an excellent body diode VF and QRR

 

Wolfspeed

Wolfspeed showed that SiC MOSFETs have made rapid advance since 1st introduction in 2011; now the 3rd generation MOSFETs have become available at 900 and 1200 volt. For on-board charging the C3M SiC MOSFETs have low switching losses and superior body diode which is ideal for the totem pole PFC topology. The high voltage rating of 1000 volt for the use of the SiC MOSFET allows operation with variable DC link to maximize efficiency. The high switching and high-efficiency operation allow onboard chargers ( OBC ) to be smaller, lighter, and overall more cost effective.

 

ON Semiconductor

ON Semiconductor has focus on portfolio expansion and secure supply chain. Unlock substrate supply, Cost @ Yield and have multiple Epitaxy supplier qualified. To have implemented a capacity expansion for SiC MOSFET and Diode to >1k WSPW until 2020. Enabling all ON backend facilities for SiC dicing and assembly. Establish new packaging capabilities to enable best thermal performance and low parasitic inductance. Since 2015 the 6inch volume production is in place and SiC products available. The SiC MOSFET Gate driver is released with flexible in Gate drive voltage, with onboard negative charge pump and propagation delays <50ns (typ 25ns).

 

Littelfuse

Littelfuse presented a reference of a 10kW 3-Level Inverter for PV Applications.

Reduced size at higher efficiency using low RDS_ON SiC MOSFETs and higher switching frequency with following results: (50kHz) at higher power (10kW), >99% peak efficiency and >1.4kW/liter Power Density. The T-type inverter topology for reduced ground current in transformer-less grid-tie inverter applications and a combination of SiC MOSFETs and IGBTs for performance and cost tradeoff in collaboration with Texas Instruments

 

GeneSiC

GeneSiC offers a wide range of 1200 – 3300 V SiC Diodes with best-in-class quality, performance, and robustness. These MOSFETs offer the highest continuous operating current for a given Rds,on and they are tested under UIS up to 5000 V with high UIS energies. GeneSiC’s MOSFETs, which will be released in Q3 of 2018, offer high reliability, robustness, and are AEC-Q101 qualified parts for automotive, industrial, and light industrial applications.

 

Summary of SiC Presentations

We see significant progress in design and applications using SiC devices for higher voltages. Mostly we see applications in the line voltage range and higher.

 

GaN Presentations

Below, I have summarized the key messages from each presenter for GaN.

Navitas

Navitas is the World’s first & only GaN power IC company working with World-class manufacturing partners. Monolithic integration (650 V eMode) including the GaN FET, the GaN Driver and the GaN Logic (control, protection) www.navitassemi.com

 

Infineon

Infineon´s CoolGaN technology for the highest efficiency and power density –600 V released for production. CoolGaN frontend is embedded in the world-class power semiconductor Fab –Innovation Fab Villach. 600 V and 400 V CoolGaN™ HEMTs are enhancement mode transistors (norm-OFF) with self-clamping gate structure. CoolGaN™ enables the highest efficiency and power density at lower system costs. The devices are used in server, telecom, adapter, and audio applications. They are released with the highest quality targets, with an application-related qualification approach. The production is front-end embedded into Infineon‘s high volume Fab in Villach (AT), for the best cost and technology roadmap. Infineon’s reliable Cool- GaN™ is in production and being shipped to first customers now, ready for mass market soon!

 

Efficient Power Conversion (EPC)

Efficient Power Conversion (EPC) stated that the technical challenges are ahead of us. Maintain technical momentum – Creating a new Moore’s Law. The growth in automotive electronics and autonomous cars is driving cost and reliability requirements. Functional integration – Lots of GaN ICs with greater and greater functionality are in development.

 

GaN Systems

ROHM and GaN Systems join Forces for GaN Power Semiconductors The customers leveraging GaN advantages with the following products:

  • 12 kW inverter; 5x smaller, 3x lighter and 50% lower Ploss
  • 1 kW solar ESS: 2x smaller, 3x lighter and eliminated the fan
  • 200 W AC adapter: 4x smaller, 3x lighter and 40 W/in3
  • 3 kW converter: 50% higher power density, 20% lower Ploss

 

EPIGAN

EPIGAN is the Industry-leading GaN material solutions supplier for next generation of Efficient Power Electronic, RF Power and Sensor devices and systems.

  • Founded in 2010 as a spin-off from IMEC
  • Headquarters and production site in Hasselt, Belgium
  • Key products: GaN-on-Si and GaN-on-SiC material solutions
  • NEW 2018: Agents’ Network developing in Asia

 

Transphorm

Transphorm presented the CORSAIR – 1.6 kW Titanium Gaming Power Supply. The TPH3205WS Transphorm’s GaN device is used in an Interleaved Bridgeless Totem-Pole PFC for high-end gaming applications.

Another application is the Bel Power 3 kW Titanium Server Power Supply with a Bridgeless Totem-Pole PFC using the TPH3205WS device in data centers.

 

Summary of GaN Presentations

We see significant progress in design and application using GaN devices for lower voltages. Mostly we see applications up to the line voltage range and below.

 

Final Thoughts

Overall, we see great acceptance for using WBG devices in new designs. The question is not to compare SiC with GaN or Silicon. It is important to choose the best technical device for the given application to reach the highest level of efficiency. Doing that shows that system approach has benefits in shrinking the unit and getting smaller passive elements in place. Mostly the total cost shows that using WBG devices does not increase the system cost.

To take the barrier down for new design the engineers need the right support.

I, together with ICC media andAspencore, and organizing the second WBG Power Conference in Munich at the Airport Hilton on the 4th of December. Last year's success encouraged us to continue this event.

 

Source: Bodo's Power Systems, August 2018