Reliability properties of low-voltage ferroelectric capacitors and memory arrays

We report on the reliability properties of ferroelectric capacitors and memory arrays embedded in a 130-nm CMOS logic process with 5LM Cu/FSG. Low voltage (<1.5 V) operation is enabled by the 70-nm thick MOCVD PZT ferroelectric films. Data loss resulting from high temperature bakes is primarily caused by the imprint effect, which shows /spl sim/1.5 eV time-to-fail activation energy. Excellent bit endurance properties are observed on fully packaged memory arrays, with no degradation up to 10/sup 13/ write/read polarization switching cycles. Retention measured after 10/sup 12/ switching cycles demonstrates no degradation relative to arrays with minimal cycling.

[1]  C. B. Sawyer,et al.  Rochelle Salt as a Dielectric , 1930 .

[2]  K. Udayakumar,et al.  Plasma Etch Processes for Embedded FRAM Integration , 2003 .

[3]  J. Moon,et al.  Enhanced Retention Characteristics of Pb(Zr, Ti)O3 Capacitors by Ozone Treatment , 2001 .

[4]  H. Jaffe,et al.  ELECTRICAL CONDUCTIVITY IN LEAD TITANATE ZIRCONATE CERAMICS , 1963 .

[5]  C. Hwang,et al.  Thermally induced voltage offsets in Pb(Zr,Ti)O3 thin films , 2000 .

[6]  J. Robertson,et al.  Band states and shallow hole traps in Pb(Zr,Ti)O3 ferroelectrics , 1995 .

[7]  P. McWhorter,et al.  Identification of paramagnetic Pb+3 defects in lead zirconate titanate ceramics , 1993 .

[8]  Y. Hayashi,et al.  Effect of imprint on operation and reliability of ferroelectric random access memory (FeRAM) , 2001 .

[9]  Ramamoorthy Ramesh,et al.  Leakage current mechanisms in lead-based thin-film ferroelectric capacitors , 1999 .

[10]  Jun Hee Lee,et al.  Fatigue and retention in ferroelectric Y‐Ba‐Cu‐O/Pb‐Zr‐Ti‐O/Y‐Ba‐Cu‐O heterostructures , 1992 .

[11]  A. Tagantsev,et al.  Polarization fatigue in ferroelectric films: Basic experimental findings, phenomenological scenarios, and microscopic features , 2001 .

[12]  B. Nielsen,et al.  Vacancy formation in (Pb,La)(Zr,Ti)O3 capacitors with oxygen deficiency and the effect on voltage offset , 2000 .

[13]  D. Dimos,et al.  Hysteresis relaxation in (Pb,La)(Zr,Ti)O3 thin film capacitors with (La,Sr)CoO3 electrodes , 1996 .

[14]  G. Fox,et al.  Relationship between PB content, crystallographic texture and ferroelectric properties of plzt thin films for FRAM® applications , 2001 .

[15]  L. Baudry,et al.  Lattice model for ferroelectric thin film materials including surface effects: Investigation on the “depolarizing” field properties , 2001 .

[16]  Hidemi Takasu,et al.  Preparation of Pb(Zr,Ti)O3 thin films on electrodes including IrO2 , 1994 .

[17]  R. Ramesh,et al.  POINT DEFECT CHEMISTRY OF METAL OXIDE HETEROSTRUCTURES , 1998 .

[18]  R. Waser,et al.  The interface screening model as origin of imprint in PbZrxTi1-xO3 thin films. II. Numerical simulation and verification , 2002 .

[19]  A. M. Glass,et al.  Principles and Applications of Ferroelectrics and Related Materials , 1977 .

[20]  D. Dimos,et al.  Optically induced absorption and paramagnetism in lead lanthanum zirconate titanate ceramics , 1992 .

[21]  D. Dimos,et al.  Driving force behind voltage shifts in ferroelectric materials , 1996 .

[22]  S. Natarajan,et al.  A 64-Mb embedded FRAM utilizing a 130-nm 5LM Cu/FSG logic process , 2004, IEEE Journal of Solid-State Circuits.

[23]  R. A. Moore,et al.  Effects of operating conditions on the fast‐decay component of the retained polarization in lead zirconate titanate thin films , 1994 .

[24]  Jun Hee Lee,et al.  Imprint and oxygen deficiency in (Pb,La)(Zr,Ti)O3 thin‐film capacitors with La‐Sr‐Co‐O electrodes , 1995 .

[25]  R. Ramesh,et al.  Influence of contact electrodes on leakage characteristics in ferroelectric thin films , 2001 .

[26]  D. Polla,et al.  Deep level transient spectroscopy characterization of ferroelectric Pb(Zr,Ti)O3 thin films , 1994 .

[27]  A. Kingon,et al.  Relaxation and leakage current characteristics of Pb1−xLax(ZryTi1−y)1−x/4O3 thin films with various Ir-based top electrodes , 2000 .

[28]  Joseph T. Evans,et al.  Voltage shifts and imprint in ferroelectric capacitors , 1995 .

[29]  Rainer Waser,et al.  The interface screening model as origin of imprint in PbZrxTi1−xO3 thin films. I. Dopant, illumination, and bias dependence , 2002 .

[30]  D. Dimos,et al.  Shallow Pb3+ hole traps in lead zirconate titanate ferroelectrics , 1993 .

[31]  R. Ramesh,et al.  Can lead nonstoichiometry influence ferroelectric properties of Pb(Zr,Ti)O3 thin films? , 1999 .

[32]  D. M. Smyth.  The role of impurities in insultating transition metal oxides , 1984 .

[33]  J. Rodriguez,et al.  Demonstration of a 4 Mb, high density ferroelectric memory embedded within a 130 nm, 5 LM Cu/FSG logic process , 2002, Digest. International Electron Devices Meeting,.

[34]  R. Waser,et al.  Imprint in ferroelectric SrBi2Ta2O9 capacitors for non-volatile memory applications , 1998 .

[35]  Theodore S. Moise,et al.  Empirical model for fatigue of PZT ferroelectric memories , 2002, 2002 IEEE International Reliability Physics Symposium. Proceedings. 40th Annual (Cat. No.02CH37320).

[36]  B. Gnade,et al.  EFFECT OF GROWTH CONDITIONS ON SURFACE MORPHOLOGY AND PHOTOELECTRIC WORK FUNCTION CHARACTERISTICS OF IRIDIUM OXIDE THIN FILMS , 1999 .