Localized Tunneling Phenomena of Nanometer Scaled High-K Gate-Stack

The 3-D simulator, which is capable of sensing potential change due to single electron's movement via a local trap inside the high-K gate-stacking block, is developed. Then, we carefully investigate how the electron's movement effects on the reliabilities of high-K gate-stack far beyond 10-nm generations. The simulation result shows that the potential change caused by a single electron's charge is about a few hundered millivolts inside the high-K gate-stacking block. By this result, random telegraph noise (RTN) and trap-assisted tunneling (TAT) are carefully investigated with respect to various applied biases, interface suboxide layer thicknesses, and the dielectric constant of high-K dielectrics (K). We also take into account the Coulomb blockade of a local trap, and then obtain several phase diagrams for distinguishing RTN and TAT under various conditions. It is then found that K = 30 can most effectively suppress the gate leakage current.