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Comment by carrigan | Hacker News Reader

The title here is slightly misleading- this isn't how LEDs are made, it is how LED dies are packaged. The more difficult part of all of this is creating the dies themselves, which is requires a clean room and all the automated tools I'm sure most people here were expecting to see.

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There are so many more parts to making an LED, too. First you need the wafer that it's grown on - either silicon carbide or alumina. The latter of which requires cones to be etched down onto the growing surface which is a significant manufacturing process all on its own. The former of which requires heating SiC until it metls at 2700C and slowly pulling out a single perfect crystal cylindrical ingot.

Then you have the actual crystal growth portion where you shove all those wafers into an evacuated chamber, heat them to a thousand degrees, spin them around, and spray them toxic pyrophoric gases. This process takes multiple hours to grow just a few microns of light producing crystals.

Then you have to grind the wafers down to the appropriate die thickness, go through multiple stages of etching, add a phosphor for white LEDs, deposit gold and ITO for electrical contacts, and use lasers to cut them into individual die. Then, finally, you can ship them to the people in the linked article. Honestly, this article is the most boring part of the whole process.

Source: I used to work in R&D for an LED manufacturer.

this is a good link, although still high level: http://www.edisontechcenter.org/LED.html

and a lab to get a better feel for how band gaps affect the spectrum: http://electron6.phys.utk.edu/phys250/Laboratories/Light%20e...

Good links indeed. And interesting. Thank you.

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