ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Experimental and modeling results for resistance degradation in thin Ba0.5Sr0.5TiO3 (BST) film capacitors with platinum (Pt) electrodes are reported. The main experimental results are as follows. Under a constant applied voltage, the current density is observed to increase with time until it reaches a maximum value. Once the maximum value is reached, the current density becomes constant with time. The barrier height at the BST/Pt (cathode) interface is observed to decrease after prolonged electrical stressing. The resistance degradation effect is observed to be reversible, particularly at elevated temperatures. Based on the experimental results, a quantitative model for resistance degradation is proposed. In this model, the increase in the current density is attributed to a decrease in the barrier height at the cathode and this decrease is assumed to have a stretched exponential dependence on time. Using experimentally determined parameters, the model calculates the current density as a function of time at various temperatures. The calculated results are verified and the model is shown to be self-consistent. Hence the model provides an accelerated method for determining the lifetime of thin BST films at the operating conditions for advanced memory applications. © 1999 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.371305
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