Investigation of electrical properties of HfO2 metal–insulator–metal (MIM) devices

This paper is devoted to the study of the electrical properties of Au/HfO 2 /TiN metal–insulator–metal (MIM) capacitors in three distinctive modes: (1) alternative mode ( C – f ), (2) dynamic regime [thermally stimulated currents, TSCs I ( T )] and (3) static mode [ I ( V )]. The electrical parameters are investigated for different temperatures. It is found that capacitance frequency C – f characteristic possesses a low-frequency dispersion that arises for high temperature ( T > 300 °C). Accordingly, the loss factor exhibits a dielectric relaxation (with an activation energy E a ~ 1.13 eV) which is intrinsically related to the diffusion of oxygen vacancies. The relaxation mechanisms of electrical defects in a dynamic regime (TSCs) analysis show that defect related to the TSC peak observed at 148.5 °C ( E a ~ 1 eV) is in agreement with impedance spectroscopy ( C – f ). On the other hand, when the MIM structures are analyzed in static mode, the I – V plots are governed by Schottky emission. The extrapolation of the curve at zero field gives a barrier height of 1.7 eV.