Determination of interface states in metal(Ag,TiN,W)−Hf:Ta2O5/SiOxNy−Si structures by different compact methods

Abstract

In this work a compact set of analytical methods for determination of the interface state densities of metal-insulator-silicon structures containing ultrathin dielectrics is constructed (high-low method, conductance method using Gps/ω–ω curves, conductance method using Gps/ω–V curves and Terman׳s method). Specific structures metal(Ag,TiN,W)−Hf:Ta2O5/SiOxNy−Si are studied in details.It has been found that the serial measurement mode is more suitable for use than the parallel one. Obtained capacitance values in serial mode can be used in majority of the cases without further corrections, if very high precision is not required. The proposed correction method for serial resistance gives substantial improvements for Gps values.At midgap all four considered methods give similar values. Terman׳s method appears to give substantially overestimated values of Dit for energies other than that of the midgap, owing to the charging of the internal interface between the higk-k layer and the interfacial SiOxNy layer.