Dielectric characteristics of MOS capacitors with rf sputtered Ta/sub 2/O/sub 5/

The dielectric properties of Ta/sub 2/O/sub 5//Si structures obtained by rf sputtering of Ta on p-Si in all Ar/O/sub 2/ mixture have been investigated. It has been found that the the formation of an extremely thin SiO/sub 2/ film at the interface between Si and Ta/sub 2/O/sub 5/ during rf sputtering is unavoidable and is an attribute of the fabrication process. This SiO/sub 2/ layer influences significantly the dielectric and the breakdown characteristics of the structures. Optimal 15 conditions giving layers with a dielectric constant of 37 have been established. A correlation has been found between the effective dielectric constant of the layers and their breakdown strength.