Stress induced degradation in RF deposited Ta/sub 2/O/sub 5/ films on silicon

Abstract

For MOS capacitors with Ta/sub 2/O/sub 5/ gate insulator, the voltage needed to maintain constant injection current is found to decrease gradually in an initial stage longer then the usual positive charge-trapping phase. The above observation can be explained by the gradual destruction of an intermediate layer of SiO/sub 2/ between the Ta/sub 2/O/sub 5/ film and the substrate. Annealing in oxygen makes this voltage decrease more pronounced, must probably because of the additional growth of the oxide layer during anneal.