Contribution of electrodes and microstructures to the electrical properties of Pb(Zr0.53Ti0.47)O3 thin film capacitors

1994 ◽  
Vol 9 (11) ◽  
pp. 2968-2975 ◽  
Author(s):  
H.N. Al-Shareef ◽  
A.I. Kingon ◽  
X. Chen ◽  
K.R. Bellur ◽  
O. Auciello
Keyword(s):  
Thin Film ◽  
Electrode Material ◽  
Bottom Electrode ◽  
Low Voltage ◽  
Order Effect ◽  
Major Effect ◽  
Leakage Currents ◽  
Ohmic Behavior ◽  
Thin Film Capacitors ◽  
Pzt Thin Film

Pb(Zr0.53Ti0.47)O3 (PZT) thin film capacitors have been fabricated with four electrode combinations: Pt/PZT/Pt/SiO2Si, RuO2/PZT/Pt/SiO2/Si, RuO2/PZT/RuO2/SiO2/Si, and Pt/PZT/RuO2/SiO2/Si. It is shown that polarization fatigue is determined largely by the electrode type (Pt vs RuO2), and microstructure has only a second-order effect on fatigue. If either the top or bottom electrode is platinum, significant polarization fatigue occurs. Fatigue-free capacitors are obtained only when both electrodes are RuO2. In contrast, the bottom electrode is found to have a major effect on the leakage characteristics of the PZT capacitors, presumably via microstructural modifications. Capacitors with bottom RuO2 electrodes show high leakage currents (J = 10−3-10−5 A/cm2 at 1 V) irrespective of the top electrode material. Capacitors with Pt bottom electrodes have much lower leakage currents (J = 10−8 A/cm2 at 1 V) irrespective of the top electrode material. At low voltage, the I-V curves show ohmic behavior and negligible polarity dependence for all capacitor types. At higher voltages, the leakage current is probably Schottky emission controlled for the capacitors with Pt bottom electrodes.

scholarly journals Synchrotron X-ray Microdiffraction Images of Polarization Switching in Epitaxial PZT Capacitors with Pt and SrRuO3 Top Electrodes

2003 ◽  
Vol 784 ◽  
Author(s):  
Dal-Hyun Do ◽  
Dong Min Kim ◽  
Chang-Beom Eom ◽  
Eric M. Dufresne ◽  
Eric D. Isaacs ◽  
...  
Keyword(s):  
Thin Film ◽  
Bottom Electrode ◽  
Sputter Deposition ◽  
Ferroelectric Polarization ◽  
X Rays ◽  
X Ray ◽  
Pzt Film ◽  
Thin Film Capacitors ◽  
Pzt Thin Film ◽  
Switchable Polarization

ABSTRACTThe evolution of stored ferroelectric polarization in PZT thin film capacitors was imaged using synchrotron x-ray microdiffraction with a submicron-diameter focused incident x-ray beam. To form the capacitors, an epitaxial Pb(Zr,Ti)O3 (PZT) thin film was deposited on an epitaxially-grown conductive SrRuO3 (SRO) bottom electrode on a SrTiO3 (STO) (001) substrate. Polycrystalline SRO or Pt top electrodes were prepared by sputter deposition through a shadow mask and subsequent annealing. The intensity of x-ray reflections from the PZT film depended on the local ferroelectric polarization. With 10 keV x-rays, regions of opposite polarization differed in intensity by 26% in our PZT capacitor with an SRO top electrode. Devices with SRO electrodes showed just a 25% decrease in the remnant polarization after 107 switching cycles. In devices with Pt top electrodes, however, the switchable polarization decreased a by 70% after only 5×104 cycles.

Low Temperature Hydrogen Induced Degradation of (Ba,Sr)TiO3 Thin Film Capacitors

1999 ◽  
Vol 596 ◽  
Author(s):  
J. D. Baniecki ◽  
C. Parks ◽  
R. B. Laibowitz ◽  
T. M. Shaw ◽  
J. Lian ◽  
...  
Keyword(s):  
Thin Film ◽  
Dielectric Relaxation ◽  
Bottom Electrode ◽  
Electrical Characterization ◽  
Asymmetric Distribution ◽  
Leakage Currents ◽  
Metal Electrodes ◽  
Thin Film Capacitors ◽  
Electrode Interface ◽  
Secondary Ion

AbstractWe have used electrical characterization and secondary ion mass spectroscopy (SIMS) to investigate the influence of hydrogen or deuterium (H/D) on the degradation of the electrical properties of metal/Ba0.7Sr0.3TiO3/metal (M/BSTO/M) thin film capacitors after forming gas annealing (FGA). Leakage and dielectric relaxation currents increase after FGA at temperatures as low as 23C. SIMS profiling shows that at 23C H/D diffuses through thin film metal electrodes and accumulates at electrode interfaces. The location (top or bottom electrode interface) of H/D accumulation is dependent on the type of electrodes and capacitor structure. The resulting asymmetric distribution of H/D leads to large voltage offsets in the C-V characteristic, asymmetric leakage currents, and increased dielectric relaxation currents. Possible mechanisms for increased leakage and relaxation currents after FGA are discussed.

Scaled PLZT Thin Film Capacitors with Excellent Endurance and Retention Performance

2000 ◽  
Vol 655 ◽  
Author(s):  
Fan Chu ◽  
Glen Fox ◽  
Tom Davenport
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Low Voltage ◽  
Volatile Component ◽  
Retention Performance ◽  
Ceramic Thin Films ◽  
Thin Film Capacitors ◽  
Pzt Thin Film ◽  
Plzt Thin Film ◽  
Plzt Thin Films

AbstractThe requirements for future ferroelectric non-volatile memories (FRAM) include lower operating voltages, higher densities and tighter design rules. In order to achieve these requirements the key component of the FRAM device, viz., the PbZrxTi1划xO3 (PZT) thin film capacitor must be scaled dimensionally to obtain reduced film thickness and capacitor area. This paper presents the ferroelectric performance of RF magnetron sputtered PLZT thin films with thickness scaled down to 1000Å. The switching performance of the thickness scaled PLZT thin films meets the requirements of 1.8V FRAM device. Though PLZT ceramic thin films, of which the fatigue is often a concern, are utilized as non-volatile component, excellent fatigue performance was observed. The scaled PLZT thin film capacitors are fatigue free up to 1011 fatigue cycles (E=200kV/cm). The scaled 1000Å PLZT thin films also showed good imprint performance. The opposite-state charge after 10 years baking at 150°C was still above the sensing level. The thickness scaled PZT thin films, showing dramatically improved ferroelectric performance, can be applied to the manufacturing of low voltage FRAM products.

Electrical Properties of PZT Thin Film Capacitors with Novel Pt-Ir Based Electrode Barriers for Nonvolatile Memories

1998 ◽  
Vol 541 ◽  
Author(s):  
Chandra S. Desu ◽  
Ramakrishna Vedula ◽  
Kwang B. Lee ◽  
Seshu B. Desu
Keyword(s):  
Thin Film ◽  
Electrical Properties ◽  
Noble Metals ◽  
Hysteresis Loops ◽  
Barrier Structure ◽  
Leakage Currents ◽  
Ferroelectric Capacitor ◽  
Nonvolatile Memories ◽  
Thin Film Capacitors ◽  
Pzt Thin Film

AbstractA new electrode barrier structure based on noble metals Pt and Ir alloys and their oxides was proposed for the integration of PZT capacitors into high density nonvolatile memories. The proposed PtIrOx/PtIr/PtIrOx structure with Pt rich compositions (∼90%) is an excellent conducting electrode for the ferroelectric capacitor and a very good diffusion barrier for species like oxygen and Si. These structures are thermally stable up to the PZT processing temperatures of 650°C. PZT deposited on these electrodes crystallized predominantly in pervoskite phase. The test capacitors showed well saturated hysteresis loops with Pr and Ec of 21.3 µC/cm2 and 43 kV/cm, respectively. An extremely low polarization fatigue of 3% after 1× 1011 repetitions and leakage currents close to those on Pt were observed.

Formation of PZT thin-film capacitors over W-plugs and low-voltage operation for high-density LSIs

2000 ◽  
Vol 83 (8) ◽  
pp. 1-7
Author(s):  
Katsuhiro Aoki ◽  
Tomoyuki Sakoda ◽  
Satoshi Hashimoto ◽  
Yukio Fukuda ◽  
Osamu Handa ◽  
...  
Keyword(s):  
Thin Film ◽  
Low Voltage ◽  
High Density ◽  
Low Voltage Operation ◽  
Thin Film Capacitors ◽  
Pzt Thin Film

Correlations Among Degradations in Lead Zirconate Titanate thin Film Capacitors

1993 ◽  
Vol 310 ◽  
Author(s):  
In K. Yoo ◽  
Seshu B. Desu ◽  
Jimmy Xing
Keyword(s):  
Thin Film ◽  
Leakage Current ◽  
Lead Zirconate Titanate ◽  
Oxygen Vacancies ◽  
Lead Zirconate ◽  
Electrical Degradation ◽  
Zirconate Titanate ◽  
Thin Film Capacitors ◽  
Pzt Thin Film ◽  
Degradation Properties

AbstractMany attempts have been made to reduce degradation properties of Lead Zirconate Titanate (PZT) thin film capacitors. Although each degradation property has been studied extensively for the sake of material improvement, it is desired that they be understood in a unified manner in order to reduce degradation properties simultaneously. This can be achieved if a common source(s) of degradations is identified and controlled. In the past it was noticed that oxygen vacancies play a key role in fatigue, leakage current, and electrical degradation/breakdown of PZT films. It is now known that space charges (oxygen vacancies, mainly) affect ageing, too. Therefore, a quantitative ageing mechanism is proposed based on oxygen vacancy migration under internal field generated by either remanent polarization or spontaneous polarization. Fatigue, leakage current, electrical degradation, and polarization reversal mechanisms are correlated with the ageing mechanism in order to establish guidelines for simultaneous degradation control of PZT thin film capacitors. In addition, the current pitfalls in the ferroelectric test circuit is discussed, which may cause false retention, imprint, and ageing.

Characterisation of the fatigued state of ferroelectric PZT thin-film capacitors

1995 ◽  
Vol 29 (1-4) ◽  
pp. 145-148 ◽  
Author(s):  
E.L. Colla ◽  
A.L. Kholkin ◽  
D. Taylor ◽  
A.K. Tagantsev ◽  
K.G. Brooks ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Film Capacitors ◽  
Pzt Thin Film

Breakdown mechanisms in PZT thin film capacitors

1995 ◽  
Vol 11 (1-4) ◽  
pp. 269-275 ◽  
Author(s):  
In Kyeong Yoo ◽  
Chang Jung Kim ◽  
Seshu B. Desu
Keyword(s):  
Thin Film ◽  
Thin Film Capacitors ◽  
Pzt Thin Film
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