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this is a crazy surprise generator project! [wrong - done on blown circuit!]

A project log for enhancement to depletion

DIY method to lower gate threshold voltage of regular MOSFETs, ultimately reversing it.

DeepSOICDeepSOIC 10/27/2016 at 23:461 Comment

I have made my experimentorture circuit, and right now I'm torturing a MOSFET with a positive voltage, feeding 0.3 uA of current into gate at 50% duty cycle (2.5 s of current, then 2.5 s of gate threshold measurement).

Gate threshold voltage (for Ids = 1 mA) was going down. Then it kinda stopped at around -0.5V. But I decided to no stop the process, and it started to go UP!!! Isn't it fascinating!

I have datalogging now, so I will post a plot when I finish it.

measurement in a mess...

UPDATE. The mosfet has changed back into enhancement mode... probably... , with gate voltage for 1 mA at about +0.25 V. It's too late now, so I have to stop the torture. I leave threshold to datalog overnight. With 13 SPS recording rate, it's going to be a big file.

UPDATE: the plot!

I started with 0.01 uA of torture current. No effect. Increased to 0.1 uA. Saw something. Increased to 0.3 uA. Now we are talking! Somewhere close to minimum, I was thinking to increase the current further, but changed my mind. Glad I did!

The wiggles on rising part are caused by me tweaking the torture current, which was reducing a little bit (the tweaks were like 0.28 -> 0.3 uA). The very fact it was reducing is interesting by itself, as it must be gate voltage going up.

I failed to stop the torture cleanly, oops! Nothing serious, though.

Discussions

Yann Guidon / YGDES wrote 10/29/2016 at 01:39 point

Plot twists !!! :-D

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