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Message started by aaron_do on Feb 6th, 2012, 6:43pm

Title: MOSFET stress
Post by aaron_do on Feb 6th, 2012, 6:43pm

Hi all,


does anybody know any good documents to read about MOSFET stress and breakdown?


thanks,
Aaron

Title: Re: MOSFET stress
Post by loose-electron on Feb 6th, 2012, 9:10pm

Sze's book covers some of this but its probably
a little out of date, unless a newer edition has been published.

What are you trying to learn about?

Title: Re: MOSFET stress
Post by aaron_do on Feb 6th, 2012, 9:36pm

Hi loose-electron,


I'm trying to learn about what kind of voltage stress a MOSFET can handle. I have some idea but mainly through talking to others about it so I wanted to see if theres some good literature on the subject.

For example, for VDS, as I understand it, we are concerned with hot-carrier injection. This limits the VDS the MOSFET can handle when it is ON. But what about when it is OFF? Can it handle a much higher VDS? I understand that there is a punch-through voltage, but I I don't have much material on it...

I'm also interested in any kind of rules of thumb that designers usually follow to avoid MOSFET stress.


thanks,
Aaron

Title: Re: MOSFET stress
Post by thechopper on Feb 7th, 2012, 8:35pm

Hi Aaron,

A MOSFET will be characterized on any process depending on the type of stress you are considering. Electrical stresses can be of different types (DC, EOS, ESD, etc). A single MOSFET (also depending whether it is on or off as you suggested) will respond differently to any of these.
DC limitations on MOSFETS I think can be found in several text books, while performance on more complicated things like EOS or ESD will be harder to find.
May be looking at some process specs will give you some tips on this.

Best
Tosei

Title: Re: MOSFET stress
Post by aaron_do on Feb 8th, 2012, 5:33pm

Thanks Tosei,


I have been looking at process specs and they give some clues, but not much details. I'll keep looking around...

regards,
Aaron

Title: Re: MOSFET stress
Post by Dan Clement on Feb 8th, 2012, 6:23pm

Aaron,

What exactly is the issue you need to solve?

It's a complicated answer as pointed out above so insight into what you are really looking for would help.

-Dan

Title: Re: MOSFET stress
Post by aaron_do on Feb 9th, 2012, 12:23am

Hi Dan,


I'm grateful that you want to help me solve my problem, but I don't actually have a circuit problem which I need solving. I'm really trying to get an idea of what kind of voltage levels my circuit can tolerate and why (key point here). I understand its complicated, and can't really be answered in a post, so I'm interested if anybody knows any useful literature.


thanks,
Aaron

Title: Re: MOSFET stress
Post by Lex on Feb 9th, 2012, 2:32am

This is such a general question, and therefor I cannot recommend any references. So maybe it is useful for you to write down in which failure mechanisms you're interested in.

As already mentioned in the posts above, the "voltage levels your circuit can tolerate" depend on the profile in time of the excitation and the observation. With these ones more or less defined you can go forward and identify the underlying mechanisms.


Title: Re: MOSFET stress
Post by aaron_do on Feb 9th, 2012, 4:47pm

Hi Lex,


It is a general question because I am looking for a reference with a general discussion - nothing too deep, but preferably with some numbers. Its not like I'm asking "what is a MOSFET used for?"...

Anyway since nobody seems to know any good ones, I'm interested in discussions on the following mechanisms: punch-through, hot carrier degradation, drain-bulk breakdown, and gate oxide breakdown. I'm not really interested in papers which go too deeply into the statistical analysis, more just a general discussion with some rules of thumb.


regards,
Aaron


Title: Re: MOSFET stress
Post by loose-electron on Feb 9th, 2012, 4:57pm

Suggest you do a search on the IEEE site.

EDS (Electron Devices Society) will probably have
most of the write-ups on this topic.

The JSSC tends to write about things behaving normally.

Title: Re: MOSFET stress
Post by aaron_do on Feb 9th, 2012, 9:30pm

Will do.

thanks,
Aaron

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