Effect of Hydrogen on leakage current characteristics of (Pb, La) (Zr, Ti )$O_3$(PLZT) thin film capacitors with Pt or Ir-based top electrodes

Pt 또는 Ir 계열의 상부전극을 갖는 (Pb, La) (Zr, Ti)$O_3$ (PLZT) 박막의 누설전류특성에 미치는 수소 열처리의 효과

  • Published : 2001.02.01

Abstract

The leakage current behaviors of PLZT capacitors with top electrodes of Pt, Ir, and $IrO_2$ are investigated before and after hydrogen forming gas anneal. The P-E hysteresis and fatigue properties of Pt/PLZT/Pt capacitors are almost recovered after recovery anneal in $O_2$ ambient. The leakage current mechanisms of PLZT capacitors with Pt and $IrO_2$ top electrodes are consistent with space-charge influenced injection model showing the strong time dependence irrespective of annealing conditions. On the other hand, the leakage current behavior of Ir/PLZT/Pt capacitor shows steady state independent of time because IrPb, conducting phase, formed at interface between Ir top and PLZT is a high conduction path. Teh leakage current mechanism of Ir/PLZT/Pt capacitor is consistent with Schottky barrier model.

상부전극, Pt, Ir, 그리고 $IrO_2$, 에 따라 수소 열처리전과 후, 그리고 회복열처리시 누설전류특성을 고찰하였다. Pt/PLZT/Pt 케페시터는 수소열처리 후에 다시 회복열처리를 수행하면 완전히 이력곡선의 회복을 보이며 또한 피로특성도 거의 회복 된다. Pt과 IrO$_2$ 상부전극의 경우의 진 누설전류 특성은 열처리조건에 관계없이 강한 시간 의존성을 갖는 space-charge influenced injection모델에 적합하다. 반면에 Ir 상부전극의 경우는 Ir과 PLZT 사이의 계면에 헝성된 전도성 상인 $IrO_2$로 인해 높은 누설전류 밀도를 보이면서 relaxation current 영역이 없이 steady state 영역을 보이는, 주로 Schottky barrier 모델에 의해 설명된다.

Keywords

References

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