Abstract
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 similar to 8.3 fF mu m(-2) (at 1 kHz) and a dielectric constant of similar to 21 have been achieved. Experimental results show that both the dielectric constant and loss tangent decrease with increasing frequency and reach a minimum at similar to 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.