Stress induced degradation in RF deposited Ta2O5 films on silicon

For MOS capacitors with Ta₂O₅ 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 SiO₂ between the Ta₂O₅ 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