Investigations of thermal annealing effects on electrical and structural properties of SrTaO based MIM capacitor

The annealing effects on dielectric and electrode materials in Ti/SrTaO/TaN/TiN/Ti/Si metal–insulator–metal (MIM) capacitors were studied. The electrical and structural properties were investigated after subjecting the samples to annealing temperatures of 500 °C, 700 °C and 900 °C. The electrical results revealed that the dielectric constant (k value) of Sr–Ta–O increased from 18 to 50 with increasing annealing temperature. This improvement in k value can be associated to the crystallization of dielectric layer. However, the leakage current density increased several orders of magnitudes with increase of the annealing temperatures. This observation was attributed to crystallization of dielectric, degradation of TaN electrode and out-diffusion of Si from the substrate.