X-Rays Watched Heat Cross a Hidden Chip Layer and Found One Wrinkle Cut Flow Fourfold

Researchers combined laser heating with ultrafast X-ray diffraction to map heat inside a layered gallium-nitride device. One micron-scale wrinkle reduced local thermal conductivity fourfold and lowered interface conductance by 25%, although the method remains a synchrotron-scale laboratory tool rather than a chip-cooling solution.