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1.
SrBi2Ta2O9 (SBT) ferroelectric thin films with different preferred orientations were deposited by pulsed laser deposition (PLD). Several
methods have been developed to control the preferred orientation of SBT thin films. For SBT films deposited directly on Pt/TiO2/SiO2/Si substrates and in situ crystallized at the deposition temperature, the substrate temperature has a significant impact
on the orientation and the remnant polarization (Pr) of the films; a higher substrate temperature benefits the formation of
(115) texture and larger grain size. The films deposited on Pt/TiO2/SiO2/Si substrates at 830 °C are (115)-oriented and exhibit 2Pr of 6 μC/cm2. (115)- and (200)-predominant films can be formed by using a La0.85Sr0.15CoO3 (LSCO) buffer layer or by annealing amorphous SBT films deposited on Pt/TiO2/SiO2/Si substrates at 450 °C using rapid thermal annealing (RTA). These films exhibit good electric properties; 2Pr of the films
are up to 12 μC/cm2 and 17 μC/cm2, respectively. The much larger 2Pr of the films deposited on the LSCO buffer layer and of the films obtained by RTA than
2Pr of the films deposited on Pt/TiO2/SiO2/Si substrates at 830 °C is attributed to a stronger (200) texture.
Received: 30 January 2001 / Accepted: 30 May 2001 / Published online: 25 July 2001 相似文献
2.
F. Kokai M. Taniwaki M. Ishihara Y. Koga 《Applied Physics A: Materials Science & Processing》2002,74(4):533-536
We deposited amorphous thin films of boron carbide by pulsed laser deposition using a B4C target at room temperature. As the laser fluence increased from 1 to 3 J/cm2, the number of 0.25–5 μm particulates embedded in the films decreased, and the B/C atomic ratio of the films increased from
1.8 to 3.2. The arrival of melt droplets, atoms, and small molecular species depending on laser fluence appeared to be involved
in the film formation. In addition, with increasing fluence the nanoindentation hardness of the films increased from 14 to
32 GPa. We believe that the dominant factor in the observed increase in the films’ hardness is the arrival of highly energetic
ions and atoms that results in the formation of denser films.
Received: 23 March 2001 / Accepted: 1 July 2001 / Published online: 2 October 2001 相似文献
3.
Yingbang Yao Bernd Ploss C. L. Mak K. H. Wong 《Applied Physics A: Materials Science & Processing》2010,99(1):211-216
BiFeO3 (BFO) ceramics were prepared by a modified solid-state-reaction method which adopts a higher heating/cooling rate during
the sintering process than usually used. It was found that the calcination temperature T
cal (from 400 to 750°C) does not influence the BFO phase formation, while the sintering temperature T
sin (from 815 to 845°C) dominates the phase purity. The optimum sintering temperature was in the range from 825 to 835°C. The
optimized samples exhibit saturated ferroelectric hysteresis loops with a remnant polarization of 13.2 μC/cm2. The measured piezoelectric coefficient d
33 was 45 pC/N. No remnant magnetization was observed in all of the samples. The pyroelectric properties were studied as a function
of temperature and frequency. A pyroelectric coefficient as high as 90 μC/m2 K was obtained at room temperature in the optimized sample. An abrupt decrease of the pyroelectric coefficient was observed
at temperatures between 70 and 80°C. On the basis of our results, BFO may have the potential for pyroelectric applications. 相似文献
4.
Zhang Qingfeng Jiang Shenglin Zeng Yike Fan Maoyan Wang Qingping Zhang Guangzu Zhang Yangyang Yu Yan Wang Jing 《Applied Physics A: Materials Science & Processing》2011,103(4):1159-1163
(Pb0.87La0.02Ba0.1)(Zr0.7Sn0.3−x
Ti
x
)O3 (PLBZST, 0.06≤x≤0.09) antiferroelectric ceramics were fabricated by conventional solid state reaction process, and their ferroelectric, dielectric,
and pyroelectric properties were systemically investigated. PLBZST with different Ti content were all confirmed to be in an
antiferroelectric phase at T=50°C, which is close to the lowest phase transition temperature. Compared with conventional FE ceramics, PLBZST antiferroelectric
ceramics exhibited higher electric field induced pyroelectric coefficient (p). As the content of Ti increased from 0.06 to 0.09, the pyroelectric coefficient increased from 1000 to 6500 μC/m2K under a 500 V/mm DC bias field. The maximum pyroelectric coefficient of 8400 μC/m2K was obtained at x=0.09 when an 850 V/mm DC bias field was applied, which is far larger than that of conventional phase transition pyroelectric
materials. Large pyroelectric response is beneficial for the development of infrared detectors and thermal imaging sensors. 相似文献
5.
T. Sameshima Y. Kaneko N. Andoh 《Applied Physics A: Materials Science & Processing》2001,73(4):419-423
50-nm thick amorphous silicon films formed on glass substrates were crystallized by rapid Joule heating induced by an electrical
current flowing in 100-nm-thick Cr strips formed adjacently to 200-nm-thick SiO2 intermediate layers. 3-μs-pulsed voltages were applied to the Cr strips. Melting of the Cr strips caused a high Joule heating
intensity of about 1×106 W/cm2. Raman scattering measurements revealed complete crystallization of the silicon films at a Joule heating energy of 1.9 J/cm2 via the SiO2 intermediate layer. Transmission electron microscopy measurements confirmed a crystalline grain size of 50–100 nm. 1-μm-long
crystalline grain growth was also observed just beneath the edge of the Cr strips. The electrical conductivity increased from
10-5 S/cm to 0.3 S/cm for 7×1017-cm-3-phosphorus-doped silicon films because of activation of the phosphorus atoms because of crystallization. The numerical analysis
showed a density of localized defect states at the mid gap of 8.0×1017 cm-3. Oxygen plasma treatment at 250 °C and 100 W for 5 min reduced the density of the defect states to 2.7×1017 cm-3.
Received: 3 April 2001 / Accepted: 9 April 2001 / Published online: 25 July 2001 相似文献
6.
G.S. Wang X.J. Meng Z.Q. Lai J. Yu J.L. Sun J.G. Cheng J. Tang S.L. Guo J.H. Chu 《Applied Physics A: Materials Science & Processing》2002,74(5):707-710
La0.5Sr0.5CoO3 (LSCO) films have been grown on Si (100) by a metalorganic chemical liquid deposition (MOCLD) technique using lanthanum acetate,
strontium acetate and cobalt acetate as the starting materials. Subsequent PbZr0.5Ti0.5O3 (PZT) films were deposited onto LSCO films by a modified sol-gel method. Field-emission scanning electron microscopy and
X-ray diffraction analysis show that PZT and LSCO films are polycrystalline and entirely perovskite phase. At an applied electric
field of 250 kV/cm, the Pt/PZT/LSCO capacitor shows no polarization fatigue after 3×109 switching cycles and an internal electric field; the remnant polarization Pr and the coercive field Ec are about 22 μC/cm2 and 73 kV/cm, respectively. The dielectric constant of PZT films is 650 at a frequency of 1 kHz.
Received: 20 February 2001 / Accepted: 6 June 2001 / Published online: 30 August 2001 相似文献
7.
G.S. Wang X.J. Meng Z.Q. Lai J. Yu J.L. Sun S.L. Guo J.H. Chu 《Applied Physics A: Materials Science & Processing》2003,76(1):83-86
Ferroelectric Bi3.25La0.75Ti3O12 (BLT) thin films have been grown on Pt/Ti/SiO2/Si substrates by chemical solution methods. X-ray diffraction analysis shows that BLT thin films are polycrystalline with
(171)-preferential orientation. Atomic force microscopy investigation shows that they have large grains about 120 nm in size.
A Pt/BLT/Pt capacitor has been fabricated and showed excellent ferroelectricity, with a remnant polarization and coercive
field of 24 μC/cm2 and 116 kV/cm, respectively. The capacitor shows no polarization fatigue up to 109 switching cycles. The optical constants (n,k) of the BLT thin films in the wavelength range 0.35–1.7 μm were obtained by
spectroscopic ellipsometry measurements, and the band-gap energy was found to be about 3.25 eV.
Received: 16 October 2001 / Accepted: 6 January 2002 / Published online: 3 June 2002
RID="*"
ID="*"Corresponding author. Fax: +86-21/65830-734, E-mail: gswang@mail.sitp.ac.cn 相似文献
8.
X. Hao J. Ma D. Zhang X. Xu Y. Yang H. Ma S. Ai 《Applied Physics A: Materials Science & Processing》2002,75(3):397-399
Transparent conducting antimony-doped tin oxide (SnO2:Sb) films were deposited on organic substrates by r.f. magnetron-sputtering. Polycrystalline films with a resistivity of
≈ 6.5×10-3 Ω cm, a carrier concentration of≈ 1.2×1020 cm-3 and a Hall mobility of ≈ 9.7 cm2 v-1 s-1 were obtained. The average transmittance of these films reached 85% in the wavelength range of the visible spectrum.
Received: 20 April 2001 / Accepted: 23 July 2001 / Published online: 17 October 2001 相似文献
9.
A. Petraru V. Nagarajan H. Kohlstedt R. Ramesh D.G. Schlom R. Waser 《Applied Physics A: Materials Science & Processing》2006,84(1-2):67-71
We present a sensitive method to simultaneously acquire the C(V ) characteristics and piezoresponse of sub-micron size ferroelectric capacitors using an Atomic Force Microscope (AFM). Model Pt/(La0.5,Sr0.5)CoO3/PbZr0.4Ti0.6 O3/(La0.5,Sr0.5)CoO3/La:SrTiO3/Si nanocapacitors were fabricated by focused ion beam milling from 100 μm2 down to 0.04 μm2. With this AFM based capacitance measurement technique we show clear “double-humped” C(V ) for all sizes with no significant change in the peak value of the εr down to capacitors with the smallest area of 0.04 μm2. The smallest capacitance measured is only of the order a few femtofarads, demonstrating the high sensitivity of the technique. Simultaneously, the piezoelectric response is recorded for each measurement, thus the technique facilitates simultaneous piezoresponse and dielectric characterization of ferroelectric memory devices. PACS 77.55.+f; 77.90.+k; 85.50.-n; 77.84.-s 相似文献
10.
We have successfully grown (1-x)Pb(Mg1/3- Nb1/3)O3-xPbTiO3 (PMN-PT) thin films with x=0.3, 0.35 and 0.4 by pulsed laser deposition. X-ray-diffraction studies reveal that the PMN-PT films grown on La0.5Sr0.5CoO3/LaAlO3 substrates form epitaxial heterostructures. Composition control and remedial measures to compensate for the lead and magnesium losses due to re-evaporation are demonstrated. As a common feature, the as-grown PMN-PT thin films exhibit a self-poling behavior. Their dielectric constants measured at room temperature vary from 1500 to 2500, depending on the PMN to PT ratios. The pyroelectric coefficient of the films varies from 160 to 300 C/m2K. The piezoelectric coefficient d33 is around 27 pm/V in the as-grown 70/30 films. A comparison of these values with the bulk PMN-PT of same compositions implies that the much-reduced piezoelectric properties in the PMN-PT films are primarily due to a substrate-clamping effect. PACS 77.84.-s; 77.65.-j; 77.80.-e 相似文献
11.
T. Watanabe T. Sameshima M. Ide 《Applied Physics A: Materials Science & Processing》2001,73(4):429-432
The fabrication of three-dimensional layered structures with 180-nm-thick TaOx top layers supported by 1.5-μm-thick Mo pillars formed on a glass substrate is presented. The photoresist used for planarization
was successfully removed through the TaOx layers using heat treatment at 270 °C with mixed vapors of ethyl alcohol and pure water at high pressure for 3 h. Vacancies
underlying the TaOx layers were consequently formed. The possibility of rapid and lateral crystallization of amorphous silicon films was demonstrated
when the silicon films formed on the TaOx overlaying the vacancy regions were irradiated using a frequency-doubled YAG laser at 250 mJ/cm2. Energy sensors using Cr/Al metal wires, with a high sensitivity of 0.07 mW/cm2, were also demonstrated using the present structure with vacancy regions for reduction of heat diffusion.
Received: 22 January 2001 / Accepted: 24 January 2001 / Published online: 27 June 2001 相似文献
12.
W. Que Y. Zhou Y.L. Lam K. Pita Y.C. Chan C.H. Kam 《Applied Physics A: Materials Science & Processing》2001,73(2):209-213
Luminescence properties from erbium (III) oxide nanocrystals dispersed in titania/organically modified silane composite thin
films were studied. Erbium oxide nanocrystals were prepared by an inverse microemulsion technique. A strong room-temperature
photoluminescence was observed at 1.531 μm, with the full width at half maximum (FWHM) of 22 nm due to intra-atomic transitions
between 4
I
13/2 and 4
I
15/2 levels in the erbium (III) ion. The shape, peak position, and FWHM of the photoluminescence signals from the composite thin
films were quite comparable to those prepared by other methods. The photoluminescence peak of the composite thin films showed
a maximum intensity at the heat-treatment temperature of 300 °C. A room-temperature green up-conversion emission at 543 nm
(4
S
3/2?4
I
15/2) was observed for the composite thin films with different heat-treatment temperatures upon excitation at 993 nm. The up-conversion
emission mechanism was explained by means of an energy-level diagram and the lifetime of the visible up-conversion emission
was measured.
Received: 10 July 2000 / Accepted: 11 July 2000 / Published online: 5 October 2000 相似文献
13.
Peter Frübing Feipeng Wang Michael Wegener 《Applied Physics A: Materials Science & Processing》2012,107(3):603-611
Relaxation processes and structural transitions in nonstretched and uniaxially stretched films of poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) and its homopolymer polyvinylidene fluoride (PVDF) for comparison were investigated with the aim of understanding the electromechanical properties of this lower-modulus ferroelectric copolymer. The mechanical and the dielectric response at the glass transition (?? a relaxation) exhibit similar temperature dependence of the relaxation time, whereas mechanical and dielectric processes above the glass transition are not related. They represent a continuous softening process within the amorphous phase and the dielectric ?? c relaxation, respectively. The latter is attributed to conformational changes of VDF segments in lamellae of spherulites constituting the nonpolar crystalline ?? phase. Furthermore, there is a contribution from melting of secondary crystallites formed in the amorphous phase during annealing or storage. Mechanically, this transition appears in nonstretched and stretched films as an accelerated decrease of the elastic modulus that terminates the rubber plateau. Dielectrically, this transition becomes visible as a frequency-independent loss peak only in stretched films, because stretching removes the ?? c relaxation, which superimposes the transition in nonstretched films. Melting of secondary crystallites is shown to appear in the homopolymer, too, though less pronounced because of more complete primary crystallisation. Stretching increases the modulus above the glass transition only slightly, and it does not significantly influence the softening process. On the other hand, stretching causes a spontaneous polarisation and introduces order within the amorphous phase, rendering it more polar. Melting of secondary crystallites provides an additional contribution to the polarisation. These findings may explain the relatively high electromechanical activity of P(VDF-HFP) but also its relatively low thermal stability. Moreover, they may be important for correct procedure and analysis of temperature-dependent dielectric measurements on partially crystalline polymers, in particular on those with less favourable sterical conditions for primary crystallisation. 相似文献
14.
S.U. Adikary A.L. Ding H.L.W. Chan 《Applied Physics A: Materials Science & Processing》2002,75(5):597-600
BaxSr1-xTiO3 thin films with a compositional gradient of x=0.3 to 1 (in 0.1 mole fraction increments) were fabricated on Pt/Ti/SiO2/Si substrates using a modified sol–gel technique. The graded film crystallised in a perovskite structure and consists of
a uniform microstructure with comparatively larger grains. The room-temperature relative dielectric constant (εr) and dielectric loss (cosδ) at 100 kHz were found to be 305 and 0.03 respectively. Dielectric peaks were not observed in
the temperature range from -20 °C to 120 °C. The dielectric constant and dielectric loss were almost independent of temperature.
Polarisation–electric field measurements at room temperature revealed a saturated but slim hysteresis loop with a remanent
polarisation (Pr) of 0.6 μC/cm2 and a coercive field (Ec) of 2.4 kV/mm. The graded film behaves as a stack of BaxSr1-xTiO3 capacitors connected in series and hence the dielectric Curie peaks are removed.
Received: 4 October 2001 / Accepted: 17 October 2001 / Published online: 23 January 2002 相似文献
15.
A simple method for patterning of thin (15–650 nm) aluminum films on glass substrates by direct, low-power, laser-thermal
oxidation in water under common laboratory conditions is demonstrated. Local heating of the metal film enhances the formation
of aluminum oxide (hydrargillite, Al2O3–3H2O) and provokes breakdown of the passivation layer followed by local corrosion at temperatures close to the boiling point
of water. Moving the focus of an Ar-ion laser (λ=488 nm) over the aluminum film with a speed of several μm/s yields grooves
flanked by hydrargillite. Upon through oxidation of the metal these structures act as electrically insulating domains. Depending
on the film thickness, the minimum width of the line structures measures between 266 nm and 600 nm. The required laser irradiation
power ranges from 1.7 mW to 30 mW. It is found that the photo-thermal oxidation process allows for writing of two-dimensional
electrode patterns.
Received: 16 July 2001 / Accepted: 23 July 2001 / Published online: 2 October 2001 相似文献
16.
T. Kamiya A. Suemasu T. Watanabe T. Sameshima I. Shimizu 《Applied Physics A: Materials Science & Processing》2001,73(2):151-159
The carrier transport property of polycrystalline silicon (poly-Si:H:F) thin films was studied in relation to film microstructure,
impurity, in situ or post-annealing treatments to obtain better carrier transport properties. Poly-Si:H:F films were prepared
from SiF4 and H2 gas mixtures at temperatures <300 °C. Dark conductivity of the films prepared at high SiF4/H2 gas flow ratio (e.g., 60/3 sccm) exhibits a high value for intrinsic silicon and its Fermi level is located near the conduction
band edge. The carrier incorporation is suppressed well, either by in situ hydrogen plasma treatment or by post-annealing
with high-pressure hot-H2O vapor. It is confirmed that weak-bonded hydrogen atoms are removed by the hot-H2O vapor annealing. In addition, evident correlation between impurity concentrations and dark conductivity is not found for
these films. It is thought that the carrier incorporation in the films prepared at high SiF4/H2 gas flow ratios is related to grain-boundary defects such as weak-bonded hydrogen. By applying hot-H2O vapor annealing at 310 °C to a 1-μm-thick p-doped (400)-oriented poly-Si:H:F film, Hall mobility was improved from 10 cm2/Vs to 17 cm2/Vs.
Received: 7 August 2000 / Accepted: 2 March 2001 / Published online: 20 June 2001 相似文献
17.
T. Sameshima Y. Kaneko N. Andoh 《Applied Physics A: Materials Science & Processing》2002,74(6):719-723
We analyzed the rapid heating properties of 50-nm-thick silicon films via 250-nm-thick SiO2 intermediate layers by heat diffusion from joule heating induced by electrical current flow in chromium strips. Numerical
heat-flow simulation resulted in that the silicon films were heated to the melting point by a joule-heating intensity above
1 MW/cm2. A marked increase in electrical conductance associated with silicon melting was experimentally detected. Taper-shaped chromium
strips detected the temperature gradient in the lateral direction caused by the spatial distribution of the joule-heating
intensity. Crystallization occurred according to the temperature gradient. A 2–4-μm lateral crystalline grain growth was demonstrated
for the silicon films.
Received: 20 November 2001 / Accepted: 22 November 2001 / Published online: 20 March 2002 相似文献
18.
F. Machalett K. Edinger J. Melngailis M. Diegel K. Steenbeck E. Steinbeiss 《Applied Physics A: Materials Science & Processing》2000,71(3):331-335
For direct writing of electrically conducting connections and areas into insulating gold oxide thin films a scanning Ar+ laser beam and a 30 keV Ga+ focused ion beam (FIB) have been used. The gold oxide films are prepared by magnetron sputtering under argon/oxygen plasma.
The patterning of larger areas (dimension 10–100 μm) has been carried out with the laser beam by local heating of the selected
area above the decomposition temperature of AuOx (130–150 °C). For smaller dimensions (100 nm to 10 μm) the FIB irradiation could be used. With both complementary methods
a reduction of the sheet resistance by 6–7 orders of magnitude has been achieved in the irradiated regions (e.g. with FIB
irradiation from 1.5×107 Ω/□ to approximately 6 Ω/□). The energy-dispersive X-ray analysis (EDX) show a considerably reduced oxygen content in the
irradiated areas, and scanning electron microscopy (SEM), as well as atomic force microscopy (AFM) investigations, indicate
that the FIB patterning in the low-dose region (1014 Ga+/cm2) is combined with a volume reduction, which is caused by oxygen escape rather than by sputtering.
Received: 30 May 2000 / Accepted: 31 May 2000 / Published online: 13 July 2000 相似文献
19.
X. Zhu S. Lu H.L.W. Chan C.L. Choy K.H. Wong 《Applied Physics A: Materials Science & Processing》2003,76(2):225-229
Compositionally graded (Ba1-xSrx)TiO3 (BST) (x:0.0∼0.25) thin films were grown on Pt (111)/TiO2/SiO2/Si (100) substrates using layer-by-layer pulsed laser deposition in the temperature range 550–650 °C. Both downgraded (Ba/Sr
ratio varying from 100/0 at the bottom surface to 75/25 at the top surface) and upgraded (Ba/Sr ratio varying from 75/25 at
the bottom surface to 100/0 at the top surface) BST films were prepared. Their microstructures were systematically studied
by X-ray diffractometry and scanning electron microscopy. A grain morphology transition from large ‘rosettes’ (>0.30 μm) to
small compact grains (70–110 nm) was observed in the downgraded BST films as the deposition temperature was increased from
550 to 650 °C. No such grain morphology transition was detected in the upgraded BST films. Dielectric measurements with metal
electrodes revealed an enhanced dielectric behavior in the downgraded films. This enhancement is mainly attributed to the
large compressive stress field built up near the interface between the downgraded film and substrate. Furthermore, the BaTiO3 layer in the downgraded BST films not only serves as a bottom layer but also as an excellent seeding layer for enhancing
the crystallization of the subsequent film layers in the downgraded films.
Received: 10 December 2001 / Accepted: 12 March 2002 / Published online: 19 July 2002
RID="*"
ID="*"Corresponding author. Fax: 86-25/359-5535, E-mail: xhzhu@public1.ptt.js.cn 相似文献
20.
The effects of TiOx diffusion barrier layer thickness on the microstructure and pyroelectric characteristics of PZT thick films were studied in this paper. The TiOx layer was prepared by thermal oxidation of Ti thin film in air and the PZT thick films were fabricated by electrophoresis deposition method (EPD). To demonstrate the barrier effect of TiOx layer, the electrode/substrate interface and Si content in PZT thick films were characterized by scanning electron microscope (SEM) and X-ray energy dispersive spectroscopy (EDS), respectively. The TiOx barrier thickness shows significant influence on the bottom electrode and the pyroelectric performance of the PZT thick films. The average pyroelectric coefficient of PZT films deposited on 400 nm TiOx layer was about 8.94 × 10−9 C/(cm2 K), which was improved by 70% than those without diffusion barrier layer. The results showed in this study indicate that TiOx barrier layer has great potential in fabrication of PZT pyroelectric device. 相似文献