Electromigration of NiSi poly gated electrical fuse and its resistance behaviors induced by high temperature

Insight is given on improved behaviors of the programmed NiSi polygated electrical fuse (eFuse) during the high temperature storage (HTS) test. By using a noble transmission electron microscopy (TEM) that includes scanning transmission electron microscopy (STEM), energy dispersive x-ray spectrometry (EDS), electron energy loss spectrometry (EELS) and nano-beam electron diffraction (NBED), microstructural behavior and phase transition of NiSi in the fuse link are painstakingly investigated before and after HTS test. It is found that improved post-resistance of eFuse is attributed to the low temperature growth of Ni₃Si₂ induced by HTS test at 250°C, which is microscopically proven by both ex-situ and in-situ TEM. In fact, Ni agglomeration, in which Ni resides around void formed in the fuse link, plays an important role of this crystallization. As results, the root causes of improved post-resistance of eFuse are qualitatively substantiated with respect to dynamic phase transformation and microstructural change in the fuse link.