Technical Insight
Toshiba serves up SiC diodes for starters
As Toshiba sends its SiC diodes out to photovoltaic markets, what can we expect next, asks Compound Semiconductor.
Toshiba is to mass manufacture SiC diodes, but plans to grab market share suggest transistors could soon follow. [Credit: Toshiba]
With the power electronics market tipped to reach epic proportions - US analyst business Lux Research has predicted $15 billion by 2020 – SiC device makers are jostling for space. Diodes from the likes of Cree, Rohm and Infineon have stormed into the photovoltaic inverter markets while transistors from many of these manufacturers are making in-roads to high-end PV and telecoms segments.
But now, a “new” entrant is vying for a piece of the SiC pie. Earlier this month, Japan-based electronics conglomerate, Toshiba, revealed volume production of Schottky Barrier diodes had started at its Himeji Operations in Hyogo Prefecture, Japan.
Claiming a “SiC line-up will meet demand for industrial and automotive applications” and revealing plans to capture a 30% chunk of the SiC power device market, the electronics heavyweight looks set to launch more than just diodes.
Pallavi Madakasira, Lux Research Analyst, is not surprised by Toshiba's relatively late entrance to this market. “We are seeing tremendous appetite from solar inverter manufacturers to boost inverter efficiency, this really is the Achilles heel of the industry today,” she says. “Toshiba has been a passive player in the semiconductor space... SiC diodes is an easy strategy.”
But the business's ambitious designs on market share are a different matter. “It's astounding that Toshiba can have such as impressive strategy,” she asserts. “The company does say it has a line-up of products, so I want to believe it has something in the works to develop. Manufacturing diodes alone is not going to get it to 30% market share.”
Clearly the next step, transistors, will prove more difficult. While many manufacturers can remove the silicon diode from PV inverters and simply drop in a SiC version, replacing, say, a silicon IGBT for a SiC MOSFET or JFET will not be so straightforward.
Admittedly manufacturers are already doing this; PV inverter architectures to date haven't changed a great deal, but change is afoot. New inverter architectures that will really make the most of SiC MOSFETs and JFETs are under development, and this is where Toshiba will need back-up to bring a product to market, just like its competitors already have.
As Madakasira points out, Cree, a vertically integrated organisation, manufactures SiC diodes, MOSFETs and modules and as such, can demonstrate its diodes and transistors work in its modules. What's more, Germany-based power supply manufacturer, Delta Energy Systems, recently announced how integrating Cree's latest generation MOSFETs boosted the efficiency of its high-power PV inverters.
At the same time, Infineon has collaborated with a Japan-based photovoltaic inverter manufacturer on SiC devices and modules. “Infineon doesn't mention the name of this company, but we know they have achieved photovoltaic inverter efficiencies of up to 99%,” says Madakasira.
“Toshiba now needs this validation, and that's not going to happen unless it finds a specific inverter partner in the industry,” she adds. “We personally are not aware that it has worked or is working with any of the big inverter manufacturers.”
Still, not surprisingly, Toshiba has a good track record of forging strategic partnerships. This time last year, the company - also a major lighting manufacturer in Japan - invested in US GaN-on-silicon LED developer, Bridgelux, to accelerate the commercialisation of LED-based lamps and fixtures.
Bridgelux's expertise with Toshiba's ability to scale up manufacturing is surely a winning combination, and as Madakasira speculates, the company could be about to try out the same approach on the power device industry. Still the Japan-based giant must make a move soon.
“Cree and Infineon have both mind and market share. Toshiba needs to get this out of the way as soon as possible to even drive any kind of limited traction in the industry,” concludes Madakasira. “Due to the downturn of the solar industry, fewer inverter players are left. If Toshiba is not already engaged with these businesses it needs to act fast.”
Bridgelux LED arrays: As Toshiba ploughs funds into Bridgelux's GaN on Si LEDs, will strategic partnerships in power inverter markets follow? [Credit: Bridgelux]
