Why does arrow in N mosfet point towards channel?

[blackhead]

Why does the arrow in an N-channel mosfet symbol point towards the
channel from the substrate?

Logically, I would have thought that because electrons from the
substrate move towards the channel to enhance it which would mean the
direction of conventional current flow will be from the channel to the
substrate.

cheers.

 

[blackhead]

Because the "body" is P-type...

                P -> N




Ummmm!  Apply some student thought to that idea ;-)

A positive gate voltage (relative to body) does what?

Attract minority carriers -- electrons -- from the p-type substrate
into the channel under the gate so enhancing it.

 

[Joerg]

Jim Thompson wrote:

[...]

An SCR is a doomsday machine in an ASIC ;-)

And in linear supplies when before the pass device ...

<duck and run>

 

[Joerg]

There ya' go ;-)

Do the minority carriers qualify for affirmative action treatment once
they made it over into the channel?

 

[Joerg]

Yes. They qualify for wealth redistribution ;-)

So electrons are usually blue?

 

[Spehro Pefhany]

So electrons are usually blue?

They must be organizers. Remove the electrons and the atoms are no
longer unionized.


Best regards,
Spehro Pefhany

 

[neon]

Why not it signefy a force fied on the substrate.

 

[Jasen Betts]

Why does the arrow in an N-channel mosfet symbol point towards the
channel from the substrate?

same reason the arrow in an NPN transistor points towards the emitter.

 

[Tim Williams]

How do you like this symbol? ;-)

http://webpages.charter.net/dawill/Images/Analog_Switch_3.gif

As for MOSFETs, the arrow represents the substrate-channel diode. It always
makes me shake my head when I see those symbols with the parasitic zener
explicitly piggybacked, as though it were an entirely seperate element
(which is isn't, though schottky-backed MOSFETs and FRED-backed IGBTs exist,
but neither is the pure MOSFET we're talking about). It's as if people
don't even know the meaning of the symbol they're using.

Tim

 

[Joerg]

Leftists electrons are always blue... always think they're entitled to
something they haven't yet received.

And that leaves holes everywhere.

 

[ehsjr]

Leftists electrons are always blue... always think they're entitled to
something they haven't yet received.

...Jim Thompson

Isn't there a charge for that?

Ed

 

[krw]

Isn't there a charge for that?

Certainly, and it's taxing.

 

[ehsjr]

1.60217733 (49) e-19

...Jim Thompson

Sheesh! 2 of those would be electronically re-volting.

Ed

 

[JosephKK]

Jim Thompson wrote:

[...]

An SCR is a doomsday machine in an ASIC ;-)

And in linear supplies when before the pass device ...

Definitely blows fuse _before_ anything else is stressed.

That is what the queer electrons (called homotrons) are supposed to
do.