摘要:

Though many technical barriers must be crossed, current trends in materials fabrication suggest several routes to integrating electrooptic and nonlinear optical materials monolithically with silicon and III-V semiconductor technology. These approaches include poled organic polymers, poled fused silica, and polycrystalline or epitaxially grown dielectric and ferroelectric oxide thin films. Optical waveguides fabricated from these materials may enable applications in integrated optics such as frequency doublers and modulators. Although the principal work in our laboratory is on oxide heterostructures on GaAs and sapphire, the introduction highlights the progress of other approaches. Because optical losses limit the feasibility of many device structures, considerable discussion is devoted to this topic. The use of atomic force microscopy to predict scattering losses. The summary is preceeded by some brief remarks about poling.

ISSN:1058-4587    

DOI:10.1080/10584589508220216

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Efficient second-harmonic generators in a waveguide structure, especially quasi-phase matched devices, are reviewed. The principle and the application of the quasi-phase matching method by periodic inverted domains are presented.

ISSN:1058-4587    

DOI:10.1080/10584589508220217

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The photoluminescent properties of epitaxial Er doped BaTiO3films have been measured over the temperature range of 15 −295 K. The characteristic Er3+emission peak energy is centered at 0.800 eV and is nearly temperature independent. The integrated peak intensity at 295 K is comparable to the intensity at 15 K. The photoluminescence decay time is 6 msec. which is comparable to what is observed in other Er doped solids. The predicted laser gain is of the order of 10 cm−1.

ISSN:1058-4587    

DOI:10.1080/10584589508220218

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Excitation photocurrent spectroscopy (EPS) was used to record photoconductivity from 200 to 600 nm for a Pb(Zr0.53Ti0.47)O3(PZT) thin film. Four spectral bands at 262, 338, and 428/472 nm were observed and assigned tentatively to originate from Pb3+, O+ +(vacancy center) and Fe3+(impurity and/or ion-doped) centers, respectively. When the band at 262 nm in the PZT film was excited using a KrF laser (248 nm), the photoconductivity at 262 nm enhances as observed in EPS. The resistivity decreases by a factor of 7 as compared to the unexposed sample that caused the P-E hysteresis loop to broaden along the polarization axis. When the band at 338 nm was pumped by a N2laser (337 nm), the P-E hysteresis loop shows a reduction in the polarization and a 26-fold increase in the resistivity. The results are consistent with the generation of shallow trapping states that dominated the production of dark current in EPS. It is suggested that KrF laser creates the conductive Pb3+hole traps and N2laser mainly generates the shallow defects having antiparallel dipoles. The presence of charge trapping centers in PZT thin films is discussed in terms of its application in optical memory devices.

ISSN:1058-4587    

DOI:10.1080/10584589508220219

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

GaAs microwave monolithic integrated circuits (MMICs) with Ba1−XSrXTiO3(BST) capacitors have been developed. Spin-coating of sol-gel solution was used to make the BST thin film. The obtained BST film has a dielectric constant of 300 that is 50 times higher than the conventional SiN one. The capacitance has the frequency roll-off over 2 GHz, which is sufficient enough for a variety of consumer applications. The implemented GaAs MMICs with on-chip BST capacitors enable the positive-bias supply and high gain performance as well as the small package outline.

ISSN:1058-4587    

DOI:10.1080/10584589508220220

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Hillock formation on Pt bottom electrode surfaces has been investigated for ⟨111⟩ Si and sapphire substrates. This paper correlates the electrical performance of Pt/PZT/Pt structured capacitors with the observed surface roughness and/or hillock presence on the Pt bottom electrode.

ISSN:1058-4587    

DOI:10.1080/10584589508220221

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Strontium titanate films have been prepared by MOCVD from Sr(thd)2and titanium isopropoxide. Ammonia was used as a carrier gas for the strontium precursor, and argon as the carrier for the titanium precursor. The films have been deposited on silicon and on Pt/Ti/SiO2/Si substrates at 700°C using N2O as the oxidizing atmosphere. The films have been characterized by X-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS) and electrical measurements. X-ray diffraction showed that the crystallization of the films was strongly dependent on their composition. Films having a ratio Sr:Ti>0.8 crystallized in the perovskite phase, while films containing a lower Sr:Ti ratio did not crystallize at all. The diffractograms of strontium rich films showed that they contained also strontium oxide and strontium carbonate crystalline phases. However no crystalline phase could be identified in the titanium rich films. RBS measurements indicate a strong interaction between the strontium titanate and the platinum films and to a lesser extent with the silicon surface. A strontium titanate film, of random orientation and a thickness of 320 nm, had a dielectric constant of 131 and a dissipation factor of about 2% at 200 kHz and a leakage current of 10−7Amp.cm−2.

ISSN:1058-4587    

DOI:10.1080/10584589508220222

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Epitaxial LiTaO3films were grown on single crystal substrates using a single molecular precursor, LiTa(OButn)6. The deposition is achieved by vaporphase hydrolysis-polycondensation reactions in a low pressure MOCVD reactor. Rocking curve of LiTaO3film grown on sapphire (0006) indicated high quality epitaxy. LiTa(OButi)6and LiTa(OButt)6precursors resulted in single phase β-Ta2O5films.

ISSN:1058-4587    

DOI:10.1080/10584589508220223

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The interactions between the electrodes and titanate ceramic materials are examined using numerical defect chemistry models. A time independent model solves for the steady-state concentrations of electrons and holes, ionized acceptors, and oxygen vacancy concentrations throughout the ferroelectric film as a function of electrical potential, temperature, and oxygen partial pressure.

ISSN:1058-4587    

DOI:10.1080/10584589508220224

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Growth of PZT thin films with large area was performed in a 6–8 inch single wafer type MOCVD system, using Pb(DPM)2(solid), (C2H5)3Pb[OCH2C(CH3)3] (liquid), Zr(O-t-C4H9)4(liquid), Ti(O-i-C3H7)4(liquid) and O2. When Pb(DPM)2was used, highly uniform PZT films with a spatial variation in film thickness of less than ±5.0% were grown on 6 and 8 inch Si wafers. However, the reproducibility of the film composition and electrical properties was quite poor. On the other hand, when (C2H5)3Pb[OCH2C(CH3)3] (Tri Ethyl neoPentOxy Lead, TEneoPOL)was used, the reproducibility of the film composition was quite good. Uniform films with spatial variations in the Pb, Zr and Ti components of less than ±1.1% and in the film thickness, refractive index and dielectric constant of respectively less than ±1.5%, ±4.1% and ±5.1% were successfully grown on a 6 inch Si wafer. The temporal variation of the film thickness, that is, the growth rate with the film growth run is less than ±1.5%. The ferroelectric hysteresis curve was observed throughout the film. The values of 2Pr and (Ec+-Ec-)/2 were 18.5μC/cm2(±16.9%) and 107kV/cm (±21.7%) in a particular PZT thin film on a 6 inch wafer, where the dielectric constant had also a rather high spatial deviation as ±18.1%

ISSN:1058-4587    

DOI:10.1080/10584589508220225

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor