I have a damaged p-type mosfet. Resistance of drain to gate: almost zero , Drain to source : below 10Mohm(some are xxxkohm).

I think ESD is injected into drain.

So. I want to know the symptoms(resistance changes) difference when gate insulator is breakdown due to gate high voltage.

Any different? Also, will drain to source resistance change or not, when ESD injected at gate?

  • \$\begingroup\$ You said that you had a gate-to-drain short after the ESD event. Doesn't that already answer your own question? If not, what exactly is unclear to you about the ESD damage? \$\endgroup\$ Jul 26, 2021 at 22:31
  • \$\begingroup\$ Ahn JIn Ho - Hi, Did you see my comment on your previous question, where I explained how to accept an answer? This is now your third question. The previous two got useful answers, but you didn't accept an answer on either question. Although accepting an answer is not required, it is encouraged as you cannot yet give thanks with a visible upvote. So, did you understand my comment? Or have you decided not to accept any answers? Or...? \$\endgroup\$
    – SamGibson
    Jul 26, 2021 at 22:41
  • \$\begingroup\$ What's it mean that "some are xxxkohm"? \$\endgroup\$
    – Hearth
    Jul 26, 2021 at 22:43
  • \$\begingroup\$ usually you see some conduction between gate and source in my experience \$\endgroup\$ Jul 27, 2021 at 7:47

1 Answer 1


High dV/dt transients to the Drain can couple thru the Miller capacitance and destroyed the insulation to gate then conduct to the body and short out G-D from an ESD arc in a nanosecond. If powered, it can then explode.

Adding ferrite beads to drain can reduce dV/dt somewhat. But if conductive exposure to ESD is possible, you may require insulation coating or a mylar shield.


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