Niobia-stabilized tantalum pentoxide (NST) - novel high-k dielectrics for low-temperature process of MIM capacitors

A novel dielectric - niobia-stabilized tantalum pentoxide (NST) - has been developed and applied in MIM capacitors. A 10% NST film has the effect of decreasing crystallization temperature by more than 150/spl deg/C and enhancing permittivity by 20%, while the leakage current stays low, compared with the properties of conventional tantalum pentoxide. These improved properties result from the fact that the doped niobia stabilizes a low-temperature hexagonal phase with high permittivity.