Enhanced deposition and dielectric property of Ta/sub 2/O/sub 5/ thin films on a rugged PtO electrode

The deposition and properties of amorphous Ta/sub 2/O/sub 5/ thin films prepared at 80(degree)C-160(degree)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(OC/sub 2/H/sub 5/)/sub 5/ precursor which increases the deposition rate and decreases the deposition temperature of Ta/sub 2/O/sub 5/ 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 Ta/sub 2/O/sub 5/ films to a value around 35 fF/(mu)m/sup 2/. A similar leakage current relation is found from both types of capacitors after plasma annealing at 300(degree)C.