There are two major well known breakdowns in CMOS transistor’s history. Not until 2015, a world first observation of the breakdown, different from soft- and hard-breakdown, named dielectric fuse breakdown, dFuse, was discovered, as a milestone when CMOS technology was moved into HKMG era. 

In this talk, I will introduce from the inception of the Ig-RTN (Random Telegraph Noise) measurement on the understanding of breakdown in 2008 and briefly describe the fundamentals of RTN technique. Later in 2015, a version 2.0 of this Ig-RTN measurement, named Ig-transient, was successfully developed to delineate the breakdown path in HKMG transistors, from which a third breakdown, named dielectric fuse breakdown, was discovered. Its origin and physical mechanism will be discussed. This breakdown relies on the understanding of a leakage path in the gate dielectric of MOSFET, especially the movement of oxygen ions and the oxygen vacancies in the gate dielectric. In the end, two major applications in memories are presented, one is in the use of One-Time-Programming memory and the other one is on the understanding of the switching phenomena involved in the operation of Resistance Random Access Memory (RRAM).