SiC Mosfet

The folks at

probably supply the SiC wafers to those who may be doing that kind of research in the U.S. They might be able to help you find what you're looking for.

These guys have no spec sheets online. I wonder if they can actually supply production quantities of their products.

Interestingly, Cree acquired UltraRF, so now they're in the all-silicon LDMOS business! Hedging their bets, it seems.

John

There are always a few manufacturers talking about it at the Power Electronics show. At the last one I noticed that one company (sorry, can't remember the name) had dropped out of the race. Others persist.

I don't recall whether anyone is actually doing production quantities, but I wouldn't expect to see SiC in any kind of standard small packages. This stuff all seems destined for large power devices, the kind of stuff that incorporates complete wafers starting at 2" diameter and going up from there; 6" wafer devices were commonly being discussed, so we're talking about things that can handle thousands, or tens of thousands, of amps.

IIRC, the big advantage to SiC is that it should run happily at 300 C, so there's little problem keeping them cool. A heat sink running at

250 C will shed a LOT of heat just by convection.

Sorry, I don't know any web resources to refer you to. I assume you've already tried Google.

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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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In an earlier post, I said: "Cree research has an ad on page 12 of the June issue of Power Electronics for their Schottky diodes. Very nice specs:

"

Cree is selling SiC Schottky diodes in TO220 packages, so apparently it isn't

*all* destined for large power devices.

The Cree website I mentioned earlier is probably the best web resource if a person wants actual parts and/or wafers.

It might be worth a call. I met them in New Mexico at a high temperaure electronics conference and they were eager to market their parts.

*all*

That's interesting, and a bit odd. I wonder why they would put a SiC semiconductor, whose main advantage is that it can run at extrememly high temps, in a package that won't take those temps? Or is this a TO220 with no epoxy?

Yes, I'll check out their web site. I'm not the OP, but I'm still interested.

thanks,

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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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In article , Jim Adney wrote: [...]

The idea is about making a high voltage Schottky not super high temperature ones.

I briefly had one designed in until I did some math on the losses. An IRF FRED won out because of the lower forward drop.

I think ST also has SiC parts now.

--
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kensmith@rahul.net   forging knowledge

*all*

I checked out the web site and was surprised to see that the SiC diodes they are selling are Shottkys. I won't pretend to understand what makes a Shottky a Shottky, but these are a bit different from Si Shottkys. (Am I even spelling that right?)

Their forward voltage drop is about the same as Si PN diodes.

Their temp rating is about the same as Si PN diodes.

They have no reverse recovery current.

They are available in voltages up to 1200 V.

So they look like they might be pretty interesting, but in none of the ways that I was expecting.

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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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*all*

A Schottky diode is a metal-semiconductor junction, like a classic point-contact/cats's whisker diode. A hunk of, say, fairly heavily doped silicon is one connection, and a metalization (aluminum, molybdenum, platinum, whatever) is the other. Schottkies have low forward drop, lots of reverse leakage, and theoretically zero reverse recovery time, since no slow minority carriers are ever injected into the junction. Most are low-voltage parts, with the highest silicon diodes good for about 200 volts reverse.

SiC and GaN have higher work functions, so have higher forward drop. So a SiC schottky has drop similar to a regular silicon PN-junction diode.

Probably package limited.

Good!

Even better!

Madison, huh? Ever heard of Imago?

John

Sorry, no. What do they do?

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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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They make atom probes, gadgets that rip apart a sample and reconstruct an 3-d image of the location and isotope of every atom.

These gadgets sell for a couple of megabucks a pop. I helped them get started and have some stock still, although I've been NIH'ed out of active involvement. Imago is a spinoff of the University material science department, and I still have fond memories of Friday beer at the student union alongside the lake, and the Frank Lloyd Wright stuff.

Nice town.

John

I checked out the web site and it looks like all they really have is a rented office suite, but that appears to be only about a mile and a half from my home. I'll have to drive by there and see what it really looks like. I never heard of them, but this town is full of UW spinoffs. Some make it and most don't. Hope yours does well.

In good weather, the Union Rerrace is the best place in the world to enjoy a good beer. There's good weather here now and I've been there twice in the past week. ;-)

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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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