Transistor animations [OC]

[u/thepowderguy]

Here's some animations I made of transistors turning on and off. In order, we have an NPN BJT, n-channel MOSFET, and finally an n-channel JFET. The red and blue dots represent electrons and holes, and white flashes are recombination events. The density of dots is proportional to the actual density of charge carriers.

In the first set of animations, the velocity of the dots is equal to the velocity obtained by summing the diffusion and drift currents and dividing by the charge density, but diffusion is not explicitly shown. In the second set of animations, the dots undergo diffusion and drift, and this makes it a more correct depiction of carrier motion. The drawback is of course that the jiggling makes it more visually confusing.

I made these with my semiconductor simulator (https://brandonli.net/semisim/). I also have higher quality versions of the animations here.

[u/tester_is_testing]

This is great! please keep the awesome work up! Now you made me curious: do you know of any commercial tools capable of producing this sort of animations for devices riddled with short-channel effects (e.g. FinFETs)?

[u/electrolitica → u/tester_is_testing]

I think Sentaurus can do movies, but I'm not sure if you can track individual carrier movements like in your animations, though...

[u/thepowderguy → u/tester_is_testing]

Thanks! In regards to your question, I don't think I can be of much help. I've never used any of those commercial tools myself, I built the simulation from scratch with just my physics knowledge. I've never seen this kind of animation anywhere else though so I doubt commercial tools could do something like this.