PZT 박막 캐퍼시터의 특성에 기여하는 PZT-전극계면층의 영향

김태호; 구준모; 민형섭; 이인섭; 김지영; Taeho Kim; June-mo Koo; Hyungsub Min; Insub Lee; Jiyoung Kim

Korean Journal of Materials Research, Vol.10, No.10, 684-690, October, 2000

Export Citation

PZT 박막 캐퍼시터의 특성에 기여하는 PZT-전극계면층의 영향

Effects of PZT-Electrode Interface Layers on Capacitor Properties

김태호, 구준모, 민형섭, 이인섭¹, 김지영

국민대학교 금속재료공학과
¹동의대학교 신소재공학과

Taeho Kim, June-mo Koo, Hyungsub Min, Insub Lee¹, and Jiyoung Kim

Department of Materials Engineering, Kookmin University, Seoul, Korea
¹Department of Materials Engineering, Dongeui University, Pusan, Korea

초록

Metal-Ferroelectric-Metal(MFM) 구조의 개퍼시터에서 Pb(Zr,Ti)O 3 (PZT) -전극 계면층이 PZT 박막 특성에 기여하는 영향을 알아보기 위하여 Pt/PZT/계면층/Pt/ TiO 2 /SiO 2 /Si 구조의 캐퍼시터를 제작하였다. 계면층으로 사용될 물질들 중에서 PbTiO 3 (PT) 층을 sol-gel 방법으로 형성하였으며, PbO, ZrO 2 ,TiO 2 층들을 reactive sputtering 방법으로 형성하였다. PZT박막을 구성하는 원소들로 이루어진 단순 산화물들의 특성을 평가하기 위하여 PbO, ZrO 2 ,TiO 2 를 계면층으로 사용하여 600 ? C 에서 열처리를 실시하였고, 이 경우에는 TiO 2 가 가장 우수하게 PZT의 결정립 크기를 미세하게 하는 효과를 보였으나, 두께가 증가함에 따라 표면 거칠기가 증가하고 anatase 상으로 남기 때문에 강유전특성이 열화되었다. 반면에 PT 박막을 계면층으로 사용한 경우에는 결정립 크기의 감소와 더불어 전기적인 특성도 향상되었다. 또한 PZT의 핵생성 위치를 판단하기 위하여 PT 삽입층의 위치를 변화하며, 실험한 결과, 하부전극과 PZT 박막의 계면에 PT 삽입층을 형성하였을 경우에 가장 효과적인 seed로서의 역할을 하였다.

In order to study effects of interfacial layers between Pb(Zr,Til)Q 3 (PZT) films and electrodes for Metal-Ferroelectric-MetaI(MFM) structure capacitors, we have fabricated the capacitors with the Pt/PZT/interfacial-layer/Pt/ TiO 2 /SiO 2 /Si structure. PbTiO 3 (PT) interfacial layers were formed by sol-gel deposition and PbO, ZrO, and TiO 2 thin layers were deposited by reactive sputtering. TiO 2 interface layers result in the finest grains of PZT(crystalline Temp. 600 ? C ) films compare to PbO 2 andZrO 2 layers. However, as the thickness of TiO 2 layer increases. PZT thin films become rough and electrical characteristics were deteriorated due to remained anatase phase. On the other hand. PT interface layers result in improved morphology of PZT films and do not significantly change ferroelectric properties. It is a also observed that seed layers at the middle and top of PZT films do not give significant effects on grain size but the PT seed layer at the interface between the bottom electrode and the PZT films results in the small grain size.

Keywords:MFM;PZT;Pt;PbO;ZrO 2;TiO 2;seed layer

[References]

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Jonse R, Zurcher P, Chu P, Taylor D, Zafar S, Jiang B, Gillespie S, Integrated Ferroelectrics, 15, 199 (1997)
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Joo JH, Lee YJ, Joo SK, Ferroelectrics, 196, 1 (1997)
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이장식, 박응철, 이병일, 주승기, 대한금속·재료학회지, 38(1), 148 (2000)
Yoo IK, Desu SB, Xing J, Materials Research Society Symposium, 310, 166 (1993)
Smith DM, Ferroelectrics, 116 (1992)
Waser R, Klee M, Integrated Ferroelectrics, 2, 23 (1992)
Raymond MV, Chen J, Smith DM, Integrated Ferroeceltrics, 83(12), 7789 (1994)
Voigt JA, Tuttle BA, Headley TJ, Lamppa DL, Materials Research Society Symposium Proc., 361, 395 (1995)
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Xu Y, Ferroelectric Materials and their Applications/ North-Holland, pp.114, 1991 (1991)
Kim HS, Bang I, Kim J, J. Kor. Phys. Soc., 35, S123 (1999)

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[2] Yamaichi S, Lesaicherre P, Yamaguchi H, Takemura K, Sone S, Yabuta H, Miyasaka K, Yoshida M, Ono H, 1995 IEDM Tech. Digest, 119 (1995)

[3] Lee K, Park Y, Lee J, Lee K, Kim J, Park J, Roh B, Kim B, Ko D, Hwang C, Kang C, Kim K, Park K, Lee J, 1995 IEDM Tech. Digest, 907 (1996)

[4] Takasu H, Integrated Ferroelectrics, 14(1) (1997)

[5] Jonse R, Zurcher P, Chu P, Taylor D, Zafar S, Jiang B, Gillespie S, Integrated Ferroelectrics, 15, 199 (1997)

[6] De Araujo C, Scott J, Taylor G, Ferroelectrics Thin Film : Synthesis and Basic Properties/ Gordon and Breach Publisher, 1996 (1996)

[7] Desu SB, Yoo IK, Integrated Ferroelectrics, 3, 365 (1993)

[8] Yoo IK, Desu SB, Xing J, MRS Symp. Proc., 310, 165 (1993)

[9] Pan WY, Yue CF, Tuttle BA, Ceram. Trans, 25, 385 (1992)

[10] Scott JF, Paz de Arajuo CA, Science, 246, 1400 (1989)

[11] Chapin LN, Mayers SA, Mrter. Res. Soc., 153 (1990)

[12] Vasant Kumar CVR, Sayer M, J. Appl. Phys., 71, 864 (1992)

[13] Joo JH, Joo SK, Extended Abs. of the 1995 Int. Conf. on solid state Device and Materials, 5124 (1995)

[14] Joo JH, Lee YJ, Joo SK, Ferroelectrics, 196, 1 (1997)

[15] Lee JS, Park EC, Kil DS, Kim KH, Lee B, Joo SK, The 3rd international meeting of pacific rim ceramic society/ 1998 (1998)

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[17] Yoo IK, Desu SB, Xing J, Materials Research Society Symposium, 310, 166 (1993)

[18] Smith DM, Ferroelectrics, 116 (1992)

[19] Waser R, Klee M, Integrated Ferroelectrics, 2, 23 (1992)

[20] Raymond MV, Chen J, Smith DM, Integrated Ferroeceltrics, 83(12), 7789 (1994)

[21] Voigt JA, Tuttle BA, Headley TJ, Lamppa DL, Materials Research Society Symposium Proc., 361, 395 (1995)

[22] Barin I, Thermochemical Data of Pure Substance/ VCH Verlags Gesel m.b.h, 1989 (1989)

[23] Xu Y, Ferroelectric Materials and their Applications/ North-Holland, pp.114, 1991 (1991)

[24] Kim HS, Bang I, Kim J, J. Kor. Phys. Soc., 35, S123 (1999)