Timeline for Why is a MOSFET triggered by Vgs and not Vgd?
Current License: CC BY-SA 3.0
9 events
| when toggle format | what | by | license | comment | |
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| Jul 4, 2011 at 20:25 | comment | added | mazurnification | @mosfet symmetry - in planar CMOS process (the IC) the shape of drain/source is determined by mosfet layout designer, but except STI effects it does not play that big role. Except special options drain/source is doped the same. Speaking from experience (logic cmos processes). | |
| Jul 4, 2011 at 15:57 | comment | added | Federico Russo | @Mike DeSimone: IIRC from college long ago in CMOS drain and source are different both in doping and in shape. (That's academic knowledge, not hands-on experience) | |
| Jul 4, 2011 at 15:17 | comment | added | Mike DeSimone | It won't be exactly symmetric because source is doped different from the drain, and might be sized differently as well. (I took this class 16 years ago, memory's rusty.) | |
| Jul 4, 2011 at 15:13 | comment | added | stevenvh | @MikeDeSimone, @mazurnification - It will look different for ICs, but I'm still not quite sure those will be symmetrical. | |
| Jul 4, 2011 at 14:04 | comment | added | mazurnification | yep mosfet from integrated circuit most likely will be fully symmetrical | |
| Jul 4, 2011 at 12:55 | comment | added | Mike DeSimone | This structure is frequently used for discrete MOSFETs. The symmetric structure is usually used for MOSFETs on integrated circuits, since they can't all share a drain. | |
| Jul 4, 2011 at 7:47 | comment | added | stevenvh | @Thomas - a V-MOSFET looks different: allaboutcircuits.com/vol_3/chpt_2/10.html. Anyway, they are very much asymmetical, so even if the picture looks different, the explanation still stands. | |
| Jul 4, 2011 at 7:15 | comment | added | Thomas O | Are you sure this is not just a vertical MOS? Is a lateral MOS different? | |
| Jul 3, 2011 at 5:32 | history | answered | stevenvh | CC BY-SA 3.0 |