RF Microwave Switches Based on Reversible Metal-Semiconductor Transition Properties of VO2 Thin Films: An Attractive Way To Realise Simple RF Microelectronic Devices

2008 ◽  
Vol 1129 ◽  
Author(s):  
Frédéric Dumas-Bouchiat ◽  
Corinne Champeaux ◽  
Alain Catherinot ◽  
Julien Givernaud ◽  
Aurelian Crunteanu ◽  
...  
Keyword(s):  
Thin Films ◽  
Geometrical Parameters ◽  
Si Substrates ◽  
Thermally Activated ◽  
Microelectronic Devices ◽  
Microwave Switches ◽  
Vo2 Thin Films ◽  
Insertion Losses ◽  
Rf Signal

AbstractMicrowave switches in both shunt and series configurations are developped using semiconductor to metal (SC-M) transition of vanadium dioxide (VO2) thin films deposited by in situ pulsed laser deposition on C-plane sapphire and SiO2/Si substrates. The influence of geometrical parameters such as the length of the switch is shown. The VO2-based switches exhibit up to 30-40 dB average isolation of the radio-frequency (RF) signal on a very wide frequency band (500 MHz-35 GHz) with weak insertion losses, when thermally activated. Furthermore, they can be electrically activated. Finally these VO2-based switches are integrated in the fabrication of innovative tunable band-stop filters which consist in a transmission line coupled with four U-shaped resonators and operate in 9-11 GHz frequency range. Its tunability is demonstrated using electrical activation of each VO2-based switch.

Interfacial adhesion of nanoporous zeolite thin films

2006 ◽  
Vol 21 (2) ◽  
pp. 505-511 ◽  
Author(s):  
Lili Hu ◽  
Junlan Wang ◽  
Zijian Li ◽  
Shuang Li ◽  
Yushan Yan
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Interfacial Adhesion ◽  
Interfacial Strength ◽  
Future Generation ◽  
In Situ Growth ◽  
Seeded Growth ◽  
Si Substrates ◽  
Film Substrate

Nanoporous silica zeolite thin films are promising candidates for future generation low-dielectric constant (low-k) materials. During the integration with metal interconnects, residual stresses resulting from the packaging processes may cause the low-k thin films to fracture or delaminate from the substrates. To achieve high-quality low-k zeolite thin films, it is important to carefully evaluate their adhesion performance. In this paper, a previously reported laser spallation technique is modified to investigate the interfacial adhesion of zeolite thin film-Si substrate interfaces fabricated using three different methods: spin-on, seeded growth, and in situ growth. The experimental results reported here show that seeded growth generates films with the highest measured adhesion strength (801 ± 68 MPa), followed by the in situ growth (324 ± 17 MPa), then by the spin-on (111 ± 29 MPa). The influence of the deposition method on film–substrate adhesion is discussed. This is the first time that the interfacial strength of zeolite thin films-Si substrates has been quantitatively evaluated. This paper is of great significance for the future applications of low-k zeolite thin film materials.

In‐Situ Fabrication of YBa2Cu3O7‐x Superconducting Thin Films Directly on Silicon Substrates with Tc0 > 77K

1989 ◽  
Vol 169 ◽  
Author(s):  
C. B. Lee ◽  
R. K. Singh ◽  
S. Sharan ◽  
A. K. Singh ◽  
P. Tiwari ◽  
...  
Keyword(s):  
Thin Films ◽  
Laser Pulses ◽  
Superconducting Film ◽  
Laser Evaporation ◽  
Silicon Substrates ◽  
Superconducting Thin Films ◽  
Si Substrates ◽  
In Situ Fabrication ◽  
Substrate Temperatures

AbstractWe report in‐situ fabrication of c‐axis textured YBa2Cu3O7‐x superconducting thin films with Tco > 77K on unbuffered silicon substrates by the biased pulsed laser evaporation (PLE) technique in the temperature range of 550‐650°C. At substrate temperatures below 550°C, no c‐axis texturing of the superconducting film was observed. The YBa2Cu3O7‐x superconducting films were fabricated by ablating a bulk YBa2Cu3O7 target by a XeCl excimer laser (λ = 308 nm, τ = 45 × 10‐9 sec) in a chamber maintained at an oxygen pressure of 0.2 torr . The thickness of the films was varied from 0.3 to 0.5 nm depending on the number of laser pulses. Extensive diffusion was observed in thin films deposited at substrate temperatures above 550°C. However, microstructurally, with increase in the substrate temperature the films exhibited larger grain size and greater degree of c‐axis texturing (measured by the ratio of the (005) and (110) X‐ray diffraction peaks). This was found to give rise to better superconducting properties with Tco exceeding 77 K for YBa2Cu3O7‐x films deposited on Si substrates at 650°C.

The 'in-situ' preparation and properties of Y-Ba-Cu-O thin films on the SrTiO/sub 3/, Al/sub 2/O/sub 3/ and Si substrates

1991 ◽  
Vol 27 (2) ◽  
pp. 1475-1478 ◽  
Author(s):  
M.I. Faley ◽  
M.E. Gershenson ◽  
N.P. Kuchta ◽  
V.S. Salun
Keyword(s):  
Thin Films ◽  
Si Substrates ◽  
In Situ Preparation

Residual Stresses in Sputtered ZnO Films on (100) Si Substrates by XRD

2009 ◽  
Vol 1201 ◽  
Author(s):  
Florine Conchon ◽  
Pierre-Olivier Renault ◽  
Philippe Goudeau ◽  
Eric Le Bourhis ◽  
Elin Sondergard ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Annealing Temperature ◽  
Protective Coatings ◽  
Zno Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates ◽  
Thermally Activated ◽  
Post Deposition

AbstractResidual stresses in sputtered ZnO films on Si are investigated and discussed. By means of X-ray diffraction, we show that as-deposited ZnO films encapsulated or not by Si3N4 protective coatings are highly compressively stressed. Moreover, a transition of stress is observed as a function of the post-deposition annealing temperature. After a heat treatment at 800°C, ZnO films are tensily stressed while ZnO films encapsulated by Si3N4 are stress-free. With the aid of in-situ X-ray diffraction, we argue that this thermally-activated stress relaxation can be attributed to a variation of the chemical composition of the ZnO films.

Real-time x-ray scattering study of sputter-deposited LaNiO3 thin films on Si substrates

1999 ◽  
Vol 569 ◽  
Author(s):  
Hsin-Yi Lee ◽  
Chih-Hao Lee ◽  
Keng S. Liang ◽  
Tai-Bor Wu
Keyword(s):  
Thin Films ◽  
Real Time ◽  
Amorphous Film ◽  
Amorphous Layer ◽  
Sputtering Deposition ◽  
X Ray ◽  
Si Substrates ◽  
Plane Normal ◽  
Integrated Intensities

ABSTRACTReal-time x-ray reflectivity and diffraction measurements under in-situ sputtering deposition conditions were performed to study the crystallization behavior of LaNiO3thin films on Si substrate. We found that an amorphous layer of 60 Å was grown in the first 6 min of the deposition and subsequently a polycrystalline overlayer was developed as observed from the in-situ x-ray reflectivity curves and diffraction patterns. Polycrystalline columnar textures of (110) and (100) were grown on the top of this amorphous film. By comparing the integrated intensities of two Bragg peaks in the plane normal of x-ray diffraction, it was found that the ability of (100)-texturization enhanced with increasing film thickness over a certain critical value.

Oxidation Kinetics of Yba2Cu3OT7-x Thin Films in the Presence of Atomic Oxygen and Molecular Oxygen by In-Situ Resistivity Measurement

1991 ◽  
Vol 230 ◽  
Author(s):  
K. Yamamoto ◽  
B. M. Lairson ◽  
J. C. Bravman ◽  
T. H. Geballe
Keyword(s):  
Thin Films ◽  
Molecular Oxygen ◽  
Atomic Oxygen ◽  
Resistivity Measurement ◽  
Oxygen Stoichiometry ◽  
Ambient Conditions ◽  
Kinetics Of Oxidation ◽  
Thermally Activated ◽  
Kinetics Of

AbstractThe kinetics of oxidation in Yba2Cu3O7-x thin films in the presence of molecular and atomic oxygen ambients have been studied. The resistivity of c-axis, a-axis, and mixed a+c axis oriented films, deposited in-situ by off-axis magnetron sputtering, was measured as a function of time subsequent to a change in the ambient conditions. The oxidation process is shown to be thermally activated and can be characterized by a diffusion model with an activation energy which varies from approximately 1.2eV in the presence of molecular oxygen to 0.6eV for a flux of 2×1015 oxygen atoms/cm2sec. In both cases, diffusivity is found to be insensitive to oxygen stoichiometry, but the rate of oxidation is found to be sensitive to the microstructure and orientation of the films.

Activation Volume for Inelastic Deformation in Polycrystalline Ag Films at Low Temperatures

1999 ◽  
Vol 594 ◽  
Author(s):  
Mauro J. Kobrinsky ◽  
Carl V. Thompson
Keyword(s):  
Thin Films ◽  
Inelastic Deformation ◽  
Activation Volume ◽  
Metallic Thin Films ◽  
Thermally Activated ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Relaxation Experiments ◽  
The Mean

AbstractThe low temperature (T < 100 °C) inelasticity of polycrystalline Ag thin films on thick substrates has been studied. In-situ Transmission Electron Microscopy and stress-relaxation experiments indicate that thermally-activated glide of dislocations through forest-dislocation obstacles is the dominant inelastic mechanism. Values of the activation volume for inelastic deformation obtained with both experiments are reported. The mean distance between obstacles along the length of moving dislocations was found to be significantly smaller than the thickness of the film and the average grain size, which explains why current models for dislocationmediated plasticity underestimate the strength of thin films. Results from these experiments on Ag are expected to be representative of other metallic thin films (e.g. Cu and Au) on substrates.

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