SrxBa(1−x)TiO3 Thin Films for Active Microwave Applications

1994 ◽  
Vol 361 ◽  
Author(s):  
J.S. Horwitz ◽  
J.M. Pond ◽  
B. Tadayan ◽  
R.C.Y. Auyeung ◽  
P.C. Dorsey ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Loss Tangent ◽  
Rocking Curve ◽  
Microwave Frequencies ◽  
X Ray ◽  
Interdigital Capacitor ◽  
Frequency Tunable ◽  
Film Dielectric ◽  
Substrate Temperatures

ABSTRACTThe dielectric constant, loss tangent and Curie temperature for SrxBa(1−x)TiO3 (SBT) thin films with x = 0.2 – 0.8 have been investigated at microwave frequencies. SBT films (0.5 -3 μm thick) were grown on (100) MgO and LaAlO3 substrates by pulsed laser deposition at substrate temperatures from 850 – 900 °C in 0.35 Torr of oxygen. Deposited ferroelectric films were single phase, highly oriented, and characterized by x-ray rocking curve widths of < 0.5°. Highly oriented SBT films with x-ray rocking curve widths of 72 arc seconds were observed. In general, the thin film dielectric constant at microwave frequencies is low (200–950) compared to the reported bulk value, but strongly dependent on the Sr/Ba ratio. Biasing of a ferroelectric interdigital capacitor (< 200 kV/cm) produces a change in the dielectric constant which resulted in a phase shift in the reflected signal (S11) measured as a function of frequency from 100 MHz to 10 GHz. The dielectric loss tangent measurement, as measured at room temperature and 9.2 GHz, ranges from 0.1 to 1.2 × 10−3 and depends on the Sr/Ba ratio. These data show that SBT thin films are suitable for the development of frequency tunable microwave circuits and components.

Optical properties of anatase TiO2 films modified by N ion implantation

2012 ◽  
Vol 90 (1) ◽  
pp. 39-43 ◽  
Author(s):  
X. Xiang ◽  
D. Chang ◽  
Y. Jiang ◽  
C.M. Liu ◽  
X.T. Zu
Keyword(s):  
Thin Films ◽  
Ion Implantation ◽  
Photoelectron Spectroscopy ◽  
Radio Frequency Magnetron Sputtering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Atomic Force ◽  
Light Region ◽  
Uv Visible ◽  
Substrate Temperatures

Anatase TiO2 thin films are deposited on K9 glass samples at different substrate temperatures by radio frequency magnetron sputtering. N ion implantation is performed in the as-deposited TiO2 thin films at ion fluences of 5 × 1016, 1 × 1017, and 5 × 1017 ions/cm2. X-ray diffraction, atomic force microscope, X-ray photoelectron spectroscopy (XPS), and UV–visible spectrophotometer are used to characterize the films. With increasing N ion fluences, the absorption edges of anatase TiO2 films shift to longer wavelengths and the absorbance increases in the visible light region. XPS results show that the red shift of TiO2 films is due to the formation of N–Ti–O compounds. As a result, photoactivity is enhanced with increasing N ion fluence.

Effect of Substrate Temperature on the Electrochromic Properties of Cobalt Hydroxide Thin Films Prepared by Reactive Sputtering

2011 ◽  
Vol 1328 ◽  
Author(s):  
KyoungMoo Lee ◽  
Yoshio Abe ◽  
Midori Kawamura ◽  
Hidenobu Itoh
Keyword(s):  
Thin Films ◽  
Substrate Temperature ◽  
Indium Tin Oxide ◽  
Large Change ◽  
Amorphous Structure ◽  
Cobalt Hydroxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Substrates ◽  
Substrate Temperatures

ABSTRACTCobalt hydroxide thin films with a thickness of 100 nm were deposited onto glass, Si and indium tin oxide (ITO)-coated glass substrates by reactively sputtering a Co target in H2O gas. The substrate temperature was varied from -20 to +200°C. The EC performance of the films was investigated in 0.1 M KOH aqueous solution. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy of the samples indicated that Co3O4 films were formed at substrate temperatures above 100°C, and amorphous CoOOH films were deposited in the range from 10 to -20°C. A large change in transmittance of approximately 26% and high EC coloration efficiency of 47 cm2/C were obtained at a wavelength of 600 nm for the CoOOH thin film deposited at -20°C. The good EC performance of the CoOOH films is attributed to the low film density and amorphous structure.

Magnetoresistance and Structure of Granular Co/Ag Thin Films

1993 ◽  
Vol 313 ◽  
Author(s):  
Mary Beth Stearns ◽  
Yuanda Cheng
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Room Temperature ◽  
Magnetization Measurements ◽  
X Ray ◽  
Conduction Electrons ◽  
Low Field ◽  
Co Concentration ◽  
Microscopy Techniques ◽  
Substrate Temperatures

ABSTRACTSeveral series of CoxAg1-x granular thin films (-3000Å) were fabricated by coevapora-tion of Co and Ag in a dual e-beam UHV deposition system at varying substrate temperatures. These films have low field magnetoresistance values as large as 31% at room temperature and 65% at liquid N2 temperature. The structure of the films was determined using magnetization measurements as well as x-ray and various electron microscopy techniques. The composition was determined using Rutherford backscattering spectroscopy. The Magnetoresistance was measured at both room and liquid N2 temperatures.We deduce from the magnetization and RBS Measurements that the films consist of Co globules embedded in a Ag Matrix and that there is no appreciable mixing of the Co and Ag atoms in the films deposited at substrate temperatures ≥ 400°K. The size of the Co globules is seen to increase with increasing Co concentration and the maximum magnetoresistance occurs in those films having the smallest Ag thickness which provides magnetic isolation of the Co globules.We suggest that the large magnetoresistance of these films arises from the same mechanism which causes the low field magnetoresistance in pure ferromagnets, namely, the scattering of the highly polarized d conduction electrons of the Co at magnetic boundaries. The large increase in the room temperature magnetoresistance of the CO/Ag films as compared to those of pure 3d ferromagnetic films is due to the distance between the magnetic boundaries being reduced to a few nanometers, because of the small size of the single domain Co globules, as compared to a few microns in 3d ferromagnets.

Hot-mesh Chemical Vapor Deposition for 3C-SiC Growth on Si and SiO2

2005 ◽  
Vol 862 ◽  
Author(s):  
Kanji Yasui ◽  
Jyunpei Eto ◽  
Yuzuru Narita ◽  
Masasuke Takata ◽  
Tadashi Akahane
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
Mesh Structure ◽  
X Ray ◽  
Si Substrates ◽  
Substrate Temperatures ◽  
Sic Films

AbstractThe crystal growth of SiC films on (100) Si and thermally oxidized Si (SiO2/Si) substrates by hot-mesh chemical vapor deposition (HMCVD) using monomethylsilane as a source gas was investigated. A mesh structure of hot tungsten (W) wire was used as a catalyzer. At substrate temperatures above 750°C and at a mesh temperature of 1600°C, 3C-SiC crystal was epitaxially grown on (100) Si substrates. From the X-ray rocking curve spectra of the (311) peak, SiC was also epitaxially grown in the substrate plane. On the basis of the X-ray diffraction (XRD) measurements, on the other hand, the growth of (100)-oriented 3C-SiC films on SiO2/Si substrates was determined to be achieved at substrate temperatures of 750-800°C, while polycrystalline SiC films, at substrate temperatures above 850°C. From the dependence of growth rate on substrate temperature and W-mesh temperature, the growth mechanism of SiC crystal by HMCVD was discussed.

Characteristics of Pentacene with Different Polymer Gate Insulators for Organic Thin-Film Transistors

2007 ◽  
Vol 124-126 ◽  
pp. 451-454 ◽  
Author(s):  
Jung Min Kim ◽  
Hyun Jung Her ◽  
J.H. Yoon ◽  
Jae Wan Kim ◽  
Y.J. Choi ◽  
...  
Keyword(s):  
Thin Films ◽  
Gate Insulator ◽  
Poly Vinyl Alcohol ◽  
Organic Thin Film ◽  
X Ray Diffraction ◽  
Polymer Substrates ◽  
X Ray ◽  
Gate Insulators ◽  
Atomic Force ◽  
Substrate Temperatures

We investigated the characteristics of pentacene thin films of different materials for gate insulators using atomic force microscope (AFM) and x-ray diffraction (XRD). The pentacene thin films are fabricated by evaporation on different polymer substrates. We used HMDS (Hexa Methyl Di Silazane), PVA (Poly Vinyl Alcohol) and PMMA (Poly Methyl Meth Acrylate) for the polymer substrates, on which pentacene is deposited at various substrate temperatures. The case of pentacene deposited on the PMMA has the largest grain size and least trap concentration. We also fabricated pentacene TFTs with the PMMA gate insulator. Pentacene TFTs with PMMA gate insulator, shows high field-effect mobility (ｕFET= 0.03 cm2/Vs) and large on/off current ratio (>105) and small threshold voltage (Vth= -6 V).

scholarly journals Partial Reduction/Re-Oxidation Processing of Y-Ba-Cu-O Sputtered Thin Films

1989 ◽  
Vol 169 ◽  
Author(s):  
F.H. Garzon ◽  
J. G. Beery ◽  
D. K. Wilde ◽  
I. D. Raistrick
Keyword(s):  
Thin Films ◽  
Rf Sputtering ◽  
Partial Reduction ◽  
Rf Power ◽  
X Ray Diffraction ◽  
X Ray ◽  
Post Annealing ◽  
Residual Oxygen ◽  
Ceramic Targets ◽  
Substrate Temperatures

AbstractThin films of Y‐Ba‐Cu‐O were produced by RF sputtering of YBa2Cu3O7‐x ceramic targets, using a variety of plasma compositions, RF power levels, and substrate temperatures. Post annealing of these films in oxygen produced superconducting films with Tc values between 40‐60 K, broad transition widths and semiconductor‐like electrical behavior above Tc. Subsequent annealing at 850°C in an inert gas with a residual oxygen partial pressure of ≤10 ppm followed by an oxygen anneal produced high quality thin films: Tc> 85 K with narrow transition widths. The structure and morphology of these films during reduction‐oxidation processing were monitored using X‐ray diffraction and electron microscopy.

Structrual Characterization and Raman Scattering of Epitaxial Aluminum Nitride Thin Films on Si(111)

1992 ◽  
Vol 242 ◽  
Author(s):  
W. J. Meng ◽  
T. A. Perry ◽  
J. Heremans ◽  
Y. T. Cheng
Keyword(s):  
Thin Films ◽  
Aluminum Nitride ◽  
Raman Scattering ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Reactive Sputter Deposition ◽  
Transmission Electron ◽  
Substrate Temperatures

ABSTRACTThin films of aluminum nitride were grown epitaxially on Si(111) by ultra-high-vacuum dc magnetron reactive sputter deposition. Epitaxy was achieved at substrate temperatures of 600° C or above. We report results of film characterization by x-ray diffraction, transmission electron microscopy, and Raman scattering.

CRYSTALLINE SrTiO3 THIN FILMS ON SILICON BY PULSED LASER DEPOSITION

2005 ◽  
Vol 19 (01n03) ◽  
pp. 533-535
Author(s):  
J. H. HAO ◽  
J. GAO
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Perovskite Oxide ◽  
Deposition Technique ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Silicon Materials

We have developed a process to grow SrTiO 3 ( STO ) thin films showing single (110) orientation directly on Si by means of pulsed laser deposition technique. The growth of STO films directly on Si has been described. The crystallinity of the grown STO films was characterized by X-ray diffraction analysis of θ-2θ scan and rocking curve. Our results may be of interest for better understanding of the growth based on the perovskite oxide thin films on silicon materials.

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