about possible breakdown of cascode structure

[zhouyuanlong]

hi,
i wonder if there is no current in cascode structure, will the mid node of the two mosfets becomes easily electrostatic breakdown? because when there is no current in cascode structure, the mid node will becomes a high impedence node, and will this node electrostaic breakdown in ic, just like the gate?
in addition, i use 65nm technology, someone can tell me how much is the drain-source breakdown voltage of the 1V standard mos?
thank you very much!

 

[shar2013]

The breakdown that you should worry about is gate to drain or gate to source. You will always have some leakage current that will limit the mid node impedance, specially in deep submicron CMOS processes.
The breakdown is not drain to source ,but drain to bulk and source to bulk which are usually much more resilient than gate drain (at least 30%). The best is to consult the manufacturer.

 

[zhouyuanlong]

The breakdown that you should worry about is gate to drain or gate to source. You will always have some leakage current that will limit the mid node impedance, specially in deep submicron CMOS processes.
The breakdown is not drain to source ,but drain to bulk and source to bulk which are usually much more resilient than gate drain (at least 30%). The best is to consult the manufacturer.

thank you very much! i have another question that is, is the drain-gate reverse breakdown voltage equal to gate-source breakdown voltage? i know the gate-source breakdown is becaus the breakdown of gate-oxide, and this is irreversible. is the drain-gate reverse breakdown on the same reason, or they are not the same and drain-gate reverse breakdown voltage will much higher than gate-source?
thank you!

 

[shar2013]

gate drain is for the same reason , the device is symmetrical

 

[zhouyuanlong]

gate drain is for the same reason , the device is symmetrical

but in staturation region, the channel is not symmetrical, will this effect the d-s breakdown voltage?