Pt 또는 Ir 계열의 상부전극을 갖는 (Pb, La) (Zr, Ti) O 3   (PLZT) 박막의 누설전류특성에 미치는 수소 열처리의 효과

윤순길; Soon-Gil Yoon

Korean Journal of Materials Research, Vol.11, No.2, 151-154, February, 2001

Pt 또는 Ir 계열의 상부전극을 갖는 (Pb, La) (Zr, Ti) O 3 (PLZT) 박막의 누설전류특성에 미치는 수소 열처리의 효과

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

윤순길

충남대학교 공과대학교 재료공학과

Soon-Gil Yoon

Department of Materilas Engineering, Chungnam National University, Daeduk Science Town, 305-764, Taejon, Korea

초록

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.

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.

Keywords:Pt;Ir;IrO top celectrode;PLZT;Leakage current mechanism;Hydrogen anneal

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[1] Nakamura T, Nakao Y, Kamisawa A, Takasu H, Appl. Phys. Lett., 65, 1522 (1994)

[2] Nakamura T, Nakao Y, Kamisawa A, Takasu H, Jpn. J. Appl. Phys. Part 1, 34, 5184 (1995)

[3] Shimizu M, Okino H, Fujisawa H, Shiosaki T, ISAF Proc. IEEE Int. Symp. Appl. Ferroelectrics, 10, 471 (1996)

[4] Hong K, You IK, Yu YS, Lee SK, Integr. Ferroelectr., 21, 511 (1998)

[5] Ishihara K, Ishikawa T, Hamada K, Onishi S, Kudo J, Sakiyama L, Integr. Ferroelectr., 6, 301 (1995)

[6] Kushida Abdelghafar K, Miki H, Torii K, Fujisaki Y, Appl. Phys. Lett., 69, 3188 (1996)

[7] Ikarashi N, Appl. Phys. Lett., 73, 1955 (1998)

[8] Han JP, Ma TP, Appl. Phys. Lett., 71, 1267 (1997)

[9] Fujisaki Y, Kushida-Abdelghafar K, Miki H, Shimamoto Y, Integr. Ferroelectr., 21, 83 (1998)

[10] Kushida-Abdelghafar K, Hiratani M, Fujisaki Y, J. Appl. Phys., 85, 1069 (1999)

[11] Stolichnov I, Tagantsev A, J. Appl. Phys., 84, 216 (1998)

[12] Aggarwal S, Perusse SR, Tipton CW, Ramesh R, Appl. Phys. Lett., 73, 1973 (1998)

[13] Wouters DJ, Willems GJ, Maes HE, Microe-lectron. Eng., 29, 249 (1995)

[14] Yoon SG, Wicaksana D, Kim DJ, Kim SH, Kingon AI, unpublished at J. Mater. Res

[15] Kim SH, Hong JG, Streiffer SK, Kingon AI, J. Mater. Res., 14, 1018 (1999)

[16] Kim SH, Hong JG, Streiffer SK, Kingon AI, J. Mater. Res., 14, 1018 (1999)