A strange miniature landscape, none of which is supposed to be there.  It’s quite small indeed - the pinnacles are each less than 1 micrometer tall, which means you’d need to stack a thousand of them on top of each other to equal one millimeter.

This landscape is what formed during plasma etching on a part of my sample where the protective photomask had been scratched - little bits of photomask got scattered all over that part of the sample, and everywhere a fragment landed, it protected the material underneath from the plasma, leaving a pinnacle.  Since everything’s so tiny, it’s maddeningly easy to scratch a sample - the merest twitch of the tweezers can do it, and probably a light brush with a feather would do the job neatly as well.  It’s a good thing they don’t allow birds in the cleanroom…

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