摘要:

Pt/Bi4Ti3O12(001)/Bi2SiO5(100)/Si(100) structures have been fabricated by the metal-organic chemical vapor deposition (MOCVD) at 500°C. Bi2SiO5film is used as a buffer layer to grow ferroelectric Bi4Ti3O12films because of its relatively high dielectric constant (εr=30). The memory window has a C-V characteristic of about 0.8 V, and the retention time estimated by the zero-bias capacitance for the Pt/100-nm-Bi4Ti3O12/30-nm-Bi2SiO5/Si/Al structure is more than 11 days.

ISSN:1058-4587    

DOI:10.1080/10584589908215614

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

SrBi2Ta2O9(SBT) thin films were directly deposited on IrO2electrode using liquid source CVD (LS-CVD) method. Bi deficient region in the SBT films, which existed near the conventional Pt bottom electrode, was successfully eliminated using IrO2bottom electrode. X-ray diffraction analysis showed our SBT films on IrO2have good crystalline quality. Satisfactory electric properties (6 μC/cm2of 2Pr and 10−6A/cm2of leakage current) were obtained

ISSN:1058-4587    

DOI:10.1080/10584589908215615

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

SrBi2Ta2O9(SBT) thin films were prepared by liquid delivery MOCVD using a double alcoholate, Sr[Ta(OC2H5)6]2. In order to crystallize the deposited films, annealing in low pressure plasma produced by RF power was conducted as well as furnace annealing in O2atmosphere. It was found that the Sr/Ta and Bi/Ta ratios in the deposited-films approached to the stoichiometric ratio as both deposition temperature and reactor pressure were lowered. An SBT thin film which was deposited at 400°C under 1 Torr and subsequently annealed in O2atmosphere at 750°C for 30 min showed relatively good ferroelectricity. Remanent polarization (Pr) and coercive field (Ec) of the film were 2.0 μC/cm2and 45 kV/cm, respectively. It was also ascertained that SBT thin films were crystallized at 650°C by annealing in oxygen plasma and showed ferroelectricity. Pr and EC of the SBT film which was annealed at 650°C in oxygen plasma with RF power of 150 W and pressure of 5 Torr were 1.5 μC/cm2and 45 kV/cm, respectively.

ISSN:1058-4587    

DOI:10.1080/10584589908215616

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

For many applications of ferroelectric ICs it is desirable to operate ferroelectric memory at the lowest possible power and voltage. One way to reduce the operating voltage is to reduce film thickness. We report on the electrical properties of MOCVD deposited PZT 40/60 and 20/80 films as a function of film thickness. As the thickness is reduced, switched polarization at saturation (P*-P⁁) is reduced, but the coercive E-field is not substantially changed. Films also have imprint and fatigue behavior that is independent of film thickness when operated at constant electric field. For films below 60nm the leakage current rises rapidly; this is likely due to the effects of film roughness. For 65nm films of the PZT 20/80 material, we observed well formed hysteresis loops and PSW> 55μC/cm2at 1.2V; polarization was greater than 90% saturated at that voltage.

ISSN:1058-4587    

DOI:10.1080/10584589908215617

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Metal-organic chemical vapor deposition (MOCVD) has been used to deposit conductive oxide RuO2thin films at different temperatures on (100) MgO and (100) LaAlO3substrates. The microstructural properties of the RuO2films have been studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution electron microscopy (HREM). Different growth and microstructural properties were observed for the films deposited on the two substrates. For example, the films on MgO are epitaxial at deposition temperatures as low as 350°C, and the films on LaAlO3are epitaxial only at deposition temperatures of 600°C and above. The epitaxial films on MgO consist of two variants with an orientation relationship given by (110) RuO2//(100) MgO and [001] RuO2//[011]MgO. The epitaxial films on LaAlO3, on the other hand, contain four variants with an orientation relationship given by (200)RuO2//(100)LaAlO3and [011] RuO2//[011] LaAlO3. The difference in growth and microstructural properties were explained based on geometrical considerations for the film and substrates. The RuO2/substrate interfaces and the RuO2domain boundaries were also investigated by TEM and HREM.

ISSN:1058-4587    

DOI:10.1080/10584589908215618

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The SBT films were deposited on Pt/Ti/SiO2/Si substrates at 550°C by plasma-enhanced metalorganic chemical vapor deposition (PEMOCVD). The films were evaluated with different rf plasma power and showed a complete single phase with highly oriented (115) texture without fluorite phase at rf power of 100 W. The SBT films deposited at 100 W have a dielectric constant of 270 and dissipation factor of 0.04 at 100 kHz. The leakage current density of films prepared at 100 W was about 3.0 × 10−8A/cm2at 170 kV/cm. The SBT films deposited at 100 W by PEMOCVD showed enough dielectric and leakage properties to apply for nonvolatile memory devices.

ISSN:1058-4587    

DOI:10.1080/10584589908215619

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The TFMLC (Thin-film Multi-level Ceramic Capacitor) is conceptually straightforward. However its relatively gradual emergence has been partly due to generic process engineering issues encountered by all practitioners which compound the normal challenges of fabricating single-level ferroelectric thin-film capacitors.

ISSN:1058-4587    

DOI:10.1080/10584589908215620

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

We have been developing our original hydrolyzed sol-gel coating solutions for the SrBi2Ta2O9(SBT) thin film. The molecular structure of the solution can be controlled by hydrolysis. We studied the SBT thin film forming process using these coating solutions with the steam curing process used together and observed lower crystallization temperature and improvement of crystal orientation.

ISSN:1058-4587    

DOI:10.1080/10584589908215621

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Ferroelectric memories (FeRAMs) are new types of memories especially suitable for mobile applications due to their unique properties like non-volatility, small DRAM-like cell size, fast read and write as well as low voltage/low power behavior. Although standard CMOS processes can be used for frontend and backend processes, FeRAM technology development has to overcome major challenges due to new materials used for capacitor formation. This work gives an overview of SrBi2Ta2O9(SBT) thin films capacitor processing using Pt as electrode material. The study describes in detail SBT formation using metal organic deposition (MOD) as well as influence of electrode thickness and capacitor patterning on SBT electrical properties. Also, results for integration of the capacitor process into a 0.5μm CMOS process with 2-layer tungsten/aluminum metallization as well as stacked capacitor results are given.

ISSN:1058-4587    

DOI:10.1080/10584589908215622

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Several recent reports have combined Ir electrodes with PbZrxTi1−xO3(PZT) made by chemical solution deposition (CSD) to produce capacitors with low fatigue rates, but the same behavior has not been reported for sputtered PZT with Ir electrodes. This paper presents a comparison of the performance of sputtered and CSD PZT capacitors with Ir electrodes. It was found that replacing the Pt top electrode with Ir was sufficient for obtaining improved fatigue performance for both sputtered and CSD deposited PZT. A comparison of Ir and Pt top electrodes shows that Ir can extend the number of useful switching cycles by 3 to 4 orders of magnitude for both sputtered and CSD deposited PZT. As has been previously observed for Pt electrodes, the fatigue with Ir top electrodes is dependent on the switching voltage. Excellent fatigue performance has been observed to 1011cycles for both 3 and 5 V switching potentials. In addition to fatigue performance, a detailed analysis of switching, retention and leakage current behavior will also be presented.

ISSN:1058-4587    

DOI:10.1080/10584589908215623

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor