A YouTube creator known as Dr. Semiconductor recently built a semiconductor cleanroom in his backyard and fabricated blue LEDs from custom‑made RAM cells. He used a sapphire wafer, which he broke into shards, cleaned with deionized water, acetone and isopropyl alcohol, and etched contact patterns with a high‑power laser purchased from an online marketplace. The laser was positioned in a bathroom to keep his dog away from the beam, and after several attempts he produced visible patterns on the wafer. He tested the etched section by applying indium and a 9 V battery, which emitted blue light, confirming the functionality of the LED. To package the devices, he used a table saw that proved unsuitable, then employed the same laser to melt away the sapphire substrate in a multi‑pass process, finally separating the LED chips. He attached wire connections using indium bumps, a material commonly used in digital cameras, and added a cerium‑doped yttrium aluminum garnet layer purchased from an online supplier to convert the blue light into white. The project is part of his open‑source Semiconductor.DIY initiative, and he plans to continue refining the process and sharing detailed instructions online.