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

Deposition and property of amorphous Ta2O5 thin films prepared at 80degreesC-160degreesC by low-pressure chemical vapor deposition (LPCVD) on PtO and Pt electrodes, respectively, are compared. It is found that the reduction of the PtO electrode during deposition could 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 to 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/mum(2). A similar leakage current relation is found from both types of capacitors after plasma annealing at 300degreesC.