Frequency-dependent dielectric response of HfTaOx-based metal–insulator–metal capacitors

Frequency dependence of dielectric response of HfTaOx-based metal–insulator–metal (MIM) capacitors (sandwich structure; with dielectric layer of different thickness) fabricated with Pt as top and bottom electrodes has been reported. A high capacitance density of ∼8.3 fF µm−2 (at 1 kHz) and a dielectric constant of ∼ 21 have been achieved. Experimental results show that both the dielectric constant and loss tangent decrease with increasing frequency and reach a minimum at ∼50 kHz, and then increase sharply. Modeling of loss tangent and dielectric constant has been attempted and the results agree well with the reported results. From frequency-dependent ac conductivity analyses, it is shown that the hopping-type conduction mechanism is responsible for the decrease in resistance with frequency.