Enhanced deposition and dielectric property of Ta2O5 thin films on a rugged PtO electrode

The deposition and properties of amorphous Ta₂O₅ thin films prepared at 80°C-160°C by low-pressure chemical vapor deposition (LPCVD) on PtO and Pt electrodes, respectively, are compared. It is found that reduction of the PtO electrode during deposition can enhance the decomposition of the Ta(OC₂H₅)₅ precursor which increases the deposition rate and decreases the deposition temperature of Ta₂O₅ films on PtO, as compared with that on a Pt electrode. Moreover, a rugged electrode structure is also formed at the same time from the reduction of PtO, which enhances the capacitance density of 10-nm-thick amorphous Ta₂O₅ films to a value around 35 fF/μm². A similar leakage current relation is found from both types of capacitors after plasma annealing at 300°C.