Volume 86, Issue 7, 01 October 1999
Index of content:
- DIELECTRICS AND FERROELECTRICITY (PACS 77)
86(1999); http://dx.doi.org/10.1063/1.371304View Description Hide Description
Five layered has been prepared in the ceramic form with a view to studying its electrical properties. X-ray and microstructural studies were employed for physical characterization. Detailed electrical property measurements were undertaken so as to understand the basic transport physics of this compound. The results of dielectric studies, dc conductivity, and ac impedance are discussed, and a defect formula for has been proposed. The investigations on this material at high temperatures and frequencies reveal its stable behavior.
86(1999); http://dx.doi.org/10.1063/1.371305View Description Hide Description
Experimental and modeling results for resistance degradation in thin (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.