Electrical destruction of amorphous tantalum and niobium oxide films

Abstract

The author presents the results of a study on the processes of the destruction of amorphous tantalum and niobium oxides in thin anodic layers on metal surfaces in strong electric fields. The kinetics of the processes under study determines the reliability of oxide dielectric capacitors. The destruction processes take place in one of two forms, i.e. a breakdown of the oxide dielectric in capacitor structures whose counterelectrode is constituted of a solid phase material (metal, semiconductor, or solid electrolyte), or an electrically stimulated growth of metal oxide crystals in metal-oxide-electrolyte capacitor structures. By studying the breakdown of a highly homogeneous oxide dielectric, it is shown that such a breakdown is preceded by storage processes (dielectric aging). A number of experimental techniques are presented for detecting, in an amorphous oxide dielectric, structural defects which accelerate film destruction processes in a strong electric field and thus are potentially dangerous under the prolonged thermoelectric stresses applied to capacitor structures. These techniques are based on structure-sensitive kinetic phenomena in amorphous metal oxide dielectrics. >