摘要:

Highly oriented LiTaO3thin films were grown on (001) sapphire substrates by pyrosol process. X-ray diffraction analysis shows that the LiTaO3crystallitec-axis is normal to the sapphire substrate. X-ray pole figures reveal that the films are also in-plane oriented, with two components of heteroepitaxy, the main one being stabilized with the (110) axes of the layer parallel to the [110] direction of the substrate. Texture components are quantified.

ISSN:1058-4587    

DOI:10.1080/10584589808012692

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The microstructural development and crystal structures of sputtered PLZT 9/65/35 films onr-plane sapphire with respect to deposition/annealing conditions were studied. The films were deposited at substrate temperatures below 500°C and annealed in the range 700° to 730°C for 1 min to 20 min for complete perovskite formation either by rapid thermal annealing (RTA) or furnace annealing (FA). The optical transparency was excellent with smooth surfaces in the stoichiometric films but reduced in the Pb-deficient films. The grain sizes in the films varied from 0.1 μm to 0.8 μm and 0.2 μm to 1.2 μm after RTA and FA respectively.

ISSN:1058-4587    

DOI:10.1080/10584589808012693

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This paper presents a comparative study of integrated pyroelectric sensors based on ferroelectric polymers. Two deposition technologies of PVDF and VDF/TrFE copolymer, both compatible with IC manufacturing, are presented. A 9 μm PVDF film is bonded on a silicon substrate using a capacitive acrylic thin film and a i μm VDF/TrFE copolymer is coated directly using a spin-coating technique. The theoretical response of both PVDF and VDF/TrFE pyroelectric sensors are calculated and related to the measured values. Peak responsivities of 4.5 V/W at 200 Hz and 3 V/W at 1kHz have been achieved for the pyroelectric sensors based on PVDF AND VDF/TrFE copolymer, respectively. Despite the responsivity of PVDF being slightly higher than that of the VDF/TrFE copolymer, the choice of which polymer to use will depend on the application and the preferred processing route.

ISSN:1058-4587    

DOI:10.1080/10584589808012694

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Recent advances in nanoscale studies of ferroelectric domains by means of scanning force microscopy (SFM) are reviewed with particular emphasis on investigation of domain structure and polarization reversal in ferroelectric thin films. Applicability of different SFM modes to domain imaging with respect to the physical properties of ferroelectrics is discussed. Examples shown here include results on domain structure observation in single crystals and films by SFM operating in the noncontact, friction, topographic and piezoresponse modes. Domain wall dynamics and fatigue effects as well as SFM spatial resolution of domain structure in thin films are addressed.

ISSN:1058-4587    

DOI:10.1080/10584589808012695

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A discussion is presented on details of dielectric breakdown in ferroelectric thin-film memories, including BST and SBT. The origin of negative differential resistivity is revisited. And subtleties of depletion widths in ferroelectric films and of elemental bismuth at the SBT/Pt electrode interface are considered.

ISSN:1058-4587    

DOI:10.1080/10584589808012696

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Pb(Zr, Ti)O3(PZT)-Silicon heterostructures were fabricated by employing the direct wafer bonding method. PZT thin films were deposited on 3 in. Pt-coated Si wafers by chemical solution deposition (CSD). The PZT films were crystallized by a rapid thermal annealing at 700°C for 60 s and characterized by measuring their ferroelectric properties. The thin films were polished by chemical-mechanical polishing (CMP) and then bonded to plain silicon wafers using a micro-cleanroom setup. The room temperature bonded wafers were annealed for 12 hours at temperatures ranging from 200°C to 450°C. The bonding energy increases from 100 mJ/cm2after room temperature bonding to 1.4 J/cm2after a 450°C annealing. Metal-ferroelectric-silicon (MFS) structures were obtained by thinning down and etching away the Pt-coated Si wafer. The MFS structures were electrically characterized by capacitance-voltage and current-voltage characteristic measurements.

ISSN:1058-4587    

DOI:10.1080/10584589808012697

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Epitaxial conductive RuO2thin films were used as bottom electrodes of Ba0.5Sr0.5TiO3(BSTO) thin-film capacitors. The BSTO showed pure (111) orientation normal to the substrate surface when grown on (200) oriented epi-RuO2on LaAlO3. The BSTO film consisted of a main body of stoichiometric bulk layer and a slightly oxygen deficiency region on the very film surface as revealed by Rutherford backscattering spectrometry. The dielectric constant of BSTO was above 400 at 10 kHz with zero dc electric field bias. A bias dc electric field modulation of the dielectric constant was observed to be more than 80% at 100 kHz at a field intensity of 6 × 105V/cm.

ISSN:1058-4587    

DOI:10.1080/10584589808012698

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Orientation distributions of Pb(Zr, Ti)O3and Pb2ScTaO6thin films deposited on various substrates and buffer layers are described. All observed textures are basically fibre textures. Only PST films deposited onshow a weak in-plane alignment, with ⟨100⟩ PST perpendicular to the film surface. PST films deposited on a Pt/(100)-Si substrate exhibit strong ⟨111⟩ fibre texute, tilted 5° to the normal. The Pt substrate has also a ⟨111⟩ fibre texture, with orientation densities as high as 60 times the random distribution (m.r.d.). On both substrates, PST films show maxima in the orientation distribution near 35 m.r.d.

ISSN:1058-4587    

DOI:10.1080/10584589808012699

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

We report for the first time Ba0.6Sr0.4TiO3(BST 60/40) thin films with Mg additive fabricated by Metalorganic decomposition technique on platinum coated silicon substrates using acetate-alkoxide precursors.[1]The structural and electrical properties of the BST thin films were greatly changed by additions of Mg. The surface morphology of the films was smooth with a dense microstructure. The typical small signal dielectric constant and the loss factor for a 0.4 μm thick undoped BST films were 450 and 0.013, respectively, at an applied frequency of 100 kHz. The dielectric loss was significantly reduced by the Mg content. The tunability (ΔC/C0) was found to change from 20.7% to 5.8% as the Mg additive content was changed from 0 to 20 mol%. The films exhibited high resistivity of the order of 1012Ω-cm even up to an applied electric field of 100 kV/cm.

ISSN:1058-4587    

DOI:10.1080/10584589808012700

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Coplanar ferroelectric phase shifters have been fabricated from thin films of barium strontium titanate (BST) and gold coplanar waveguide. The ability for these devices to provide a variable phase shift is based upon the change in dielectric constant of the BST with an applied de bias. We have fabricated coplanar phase shifters by three different series of fabrication steps. For each of the three devices, MgO was used as the substrate, and the BST films were deposited by laser ablation. We describe the coplanar design, material deposition, and the high frequency testing. The phase shifters were tested at frequencies up to 35 GHz.

ISSN:1058-4587    

DOI:10.1080/10584589808012701

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor