Saturday May 10, 2014
Resembling arrays of flaming islands, these formations are actually microscopic, etched out of semiconductor.
This semiconductor material is what we use to make microscopic lasers - we start with a vast, featureless sheet of semiconductor and cover certain areas with a protective layer of glassy photoresist. Then we blast the whole thing with high-energy plasma. The plasma eats away anything that’s not protected by photoresist, leaving behind mesas and pillars and islands. In this picture, the “flames” are actually wisps of photoresist, partially eaten away by the plasma.
The tricky bit is to get the structure sides to be vertical and clean - we spend a lot of time tweaking the mixture of gases that make up the plasma. This picture is from one of my labmate Qing’s many etching tests.
I can’t help seeing creatures in the photoresist scraps - I see a jackal and a lion, playing tag.