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

-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

| 1962 | I love to cook with wine. Sometimes I even put it in the food.

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:

Quote: "... SiC Junction Transistors (SJT) ..."

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

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

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.

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com

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

-- Seven Transistor Labs Electrical Engineering Consultation Website: