MOSFET hfe Beta current gain.

You're letting the symbol confuse you. It's not an IGBT, it's a BJT-current-driven-into-channel MOS device, whatever you might call that ;-) ...Jim Thompson

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I vote that it is a some "bastard" J-FET, that have the PN-gate forward biased?:

"Gate Oxide Free SiC Switch"

"Compatible with Si MOSFET/IGBT Gate Drive ICs"

"Gate On Voltage VGSON" 3,5V figure 4 (actually figure 7)

Glenn

Here it is called a:

GeneSiC Releases 25 mOhm/1700 V Silicon Carbide Transistors:

Glenn

After some more pondering I realize it's a giant _lateral_ NPN, which gets the voltage wa-a-a-ay up.

(Lateral PNP's on my custom microchips typically have breakdown voltages in excess of 30V, on an otherwise 5V process.) ...Jim Thompson

Cool, an SiC bipolar transistor.

I've seen a strange effect in phemts, both depletion and enhancement mode devices. As you raise the gate voltage, the drain currrent goes way up as the gate begins to draw current, around +0.6 volts or so, almost a bipolar effect on top of the usual jfet-like behavior.

After all, JFETs are nothing more than UJTs with a very thin active channel area (so the gate causes cutoff) and a short channel length (so the conductivity modulation is generally small).

I haven't been able to observe much if any effect with generic silicon JFETs, but perhaps the structure of PHEMTs does something. The channel is a thin 2DEG, it might be the conductivity modulation affects the entire bulk and massively increases conductivity.

Tim

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