MIT researchers have developed a new technique to measure heat flow through multilayered electronic materials by combining ultrafast X-rays with laser pulses. Unlike traditional optical methods such as time domain thermal reflectance, this approach can penetrate multiple layers and resolve heat transfer at the nanoscale. Applied to a gallium nitride-on-silicon test device, the method revealed a fourfold reduction in heat dissipation at a single micron-scale wrinkle defect and a 25% drop across material interfaces — effects previously undetectable. The technique could help chip designers understand and mitigate overheating in increasingly compact, power-dense electronics used in AI, wearables, and clean energy systems. A leading semiconductor industry consortium has already expressed interest in collaboration.
