Current transport mechanisms in metal – high-k dielectric – silicon structures

Abstract

The mechanism of current transport in several high k -dielectric, including rare earth metal oxides (Gd₂O₃, Nd₂O₃), ternary compounds (LaLuO₃) and rare earth metal silicate (LaSiOx) thin films on silicon was studied using current-voltage ( I - V ) and conductance-frequency measurements at temperatures 100-300 K. It was shown that the current through the dielectric layer is controlled either by Pool-Frenkel mechanism of trap-assisted tunneling or by Mott’s variable range hopping conductance through the localized states near the Fermi level. From the results of measurements, the dynamic dielectric constant k of the material, energy positions and bulk concentrations of traps inside the dielectric layers were determined.