13.4 A Self-Programming PUF Harvesting the High-Energy Plasma During Fabrication

Ambient energy harvesting exploits existing energy for powering ICs and has been expanding operation space and application field of IC electronics. If an existing high energy source yet unexploited by ICs could be found, a new IC functionality could emerge. As the unexploited existing high energy source, this paper discovered highenergy plasma in a semiconductor fabrication process (Fig. 13.4.1). Plasma-based Reactive lon Etching (RIE) is one mainstream etching instrument in the semiconductor fabrication. The high-energy plasma ions are used to process silicon and metal layers but, as well-known as an antenna effect, the ion charging current during the metal layer process is strong enough to breakdown a transistor gate oxide. By harvesting stable power from this high-energy etching plasma, a circuit operating during its fabrication process can be realized, namely Fetal-Movement Circuit (FMC).