Decent Schottky diodes for bootstrap - 404

Working on a project that needs a high voltage Schottky for
bootstrapping the high side driver, I'm not finding the combo
of high (200V) voltage and low (<<10nS) reverse recovery
time. I think this is because the HV devices have a parallel PN
guardring. And of course I'd also like a nice low reverse leakage,
which is what the guardring gives you. And a SPICE model
would be nice.

Going through Digi-Key and Mouser I came up empty handed
by the time I got through my gotta-haves.

Anybody run across a really superior Schottky device or
a vendor that stands above the rest? Maybe a distributor
who sells modest quantities in die form?

why donot you try Silicon carbide diodes . i heared those diodes are High voltage and high speed devices ..

just my humble opinion.

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why donot you try Silicon carbide diodes . i heared those diodes are High voltage and high speed devices ..

just my humble opinion.

Second the motion on Silicon Carbide schottky diodes.

Cree produces devices in the 600 to 1700 volt range.

I think, regular "ultrafast" silicon diodes like US1M are best suited for HV bootstrap purposes.

As far as i know , anything under 50ns is considered ultra fast recovery diode ,isn't 10ns is very low ?
is it really nesseary to have such Trr in high side drivers ??!!

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As far as i know , anything under 50ns is considered ultra fast recovery diode ,isn't 10ns is very low ?
is it really nesseary to have such Trr in high side drivers ??!!

I'm looking to go to an insane fSW on a PWM buck, and
make it work up to 90% duty (so, a very low pulse low
time for the bootstrap to do its thing). Even 10nS is a
lot.

Maybe this is one of the reasons nobody does it. But
it's my job to try.

Silicon schottky diodes won't work out then. At high voltages, schottky diodes just tend to lose their favor vs silicon diodes.

SiC devices might, be a decent option, if you can find them in a low inductance package.

I'm wondering if your driver can even work properly with such high slew rates...

Well, that's the whole point of the exercise - very high
slew rates are possible, in this (RF) technology, provided I
can keep it fed.

What I see in digging, and have experienced back when
I worked at a place that let people design their own device
structures as they pleased, is that higher voltage Schottky
diodes need a PN guardring, and the guardring ends up
carrying a fair bit of the current once Vf in the actual
Schottky region rises up, leading to charge storage that
a real, plain Schottky wouldn't exhibit (if you could in
fact make one that behaved acceptably, without GR).

Radius of curvature is just too small in a bare Shottky
junction, to support very high voltage.

Looking at GaN and SiC Schottky diodes, their Vf would
eat up all my low voltage supply headroom.