Deposition Of BaTiO3 Thin Films And MgO Buffer Layers On Patterned GaAs Substrates For Integrated Optics Applications

2003 ◽  
Vol 784 ◽  
Author(s):  
Ding-Yuan Chen ◽  
Timothy E. Murphy ◽  
Jamie D. Phillips
Keyword(s):  
Thin Films ◽  
Integrated Optics ◽  
Deposition Process ◽  
Buffer Layers ◽  
Film Stress ◽  
Thin Film Stress ◽  
Heating And Cooling ◽  
Gaas Substrates ◽  
Electro Optic ◽  
Optic Waveguide

ABSTRACTThis work addresses the need for thick layers of ferroelectric thin films on semiconductors for integrated optics applications. The deposition of BaTiO3 thin films with MgO buffers on patterned GaAs substrates is presented as an approach to achieve crack-free optical waveguiding structures. Cracking and peeling of the thin films are observed on patterns with lateral dimensions exceeding 60 microns and nearly crack-free thin films for patterns with lateral dimensions of a few microns. The cracking and peeling of the thin films is attributed to thermal expansion mismatch during the heating and cooling steps of the deposition process. A thin film stress and fracture model is used to analyze the phenomenon. Reduced cracking and peeling on the patterned features are attributed to strain relief on the patterned features. The inclusion of thick AlxOy buffer layers obtained through wet-oxidation of AlGaAs prior to BaTiO3/MgO deposition are presented as a means of obtaining electro-optic waveguide structures on GaAs.

MBE growth of high quality InAsSb thin films on GaAs substrates with GaSb as buffer layers

2020 ◽  
Vol 542 ◽  
pp. 125688
Author(s):  
Yong Li ◽  
Xiaoming Li ◽  
Ruiting Hao ◽  
Jie Guo ◽  
Yunpeng Wang ◽  
...  
Keyword(s):  
Thin Films ◽  
Buffer Layers ◽  
High Quality ◽  
Mbe Growth ◽  
Gaas Substrates

Measurement of Thin-Film Stress, Stiffness, and Strength Using an Enhanced Membrane Pressure-Bulge Technique

2003 ◽  
Vol 795 ◽  
Author(s):  
Aaron J. Chalekian ◽  
Roxann L. Engelstad ◽  
Edward G. Lovell
Keyword(s):  
Thin Films ◽  
Microelectromechanical Systems ◽  
Applied Pressure ◽  
High Strength ◽  
Film Stress ◽  
Intrinsic Stress ◽  
Positive Pressure ◽  
Bulge Test ◽  
Thin Film Stress ◽  
The One

ABSTRACTAccurate mechanical properties of thin films are essential for viable design and fabrication of semiconductor devices and microelectromechanical systems. Relevant properties of thin films such as intrinsic stress, biaxial modulus, and fracture strength can be significantly different than their corresponding bulk values, and much more difficult to measure. However, such data can be obtained from the pressure-deflection response of clamped freestanding membranes, i.e., the so-called pressure-bulge test. Experimental challenges include membrane leakage prevention, ensuring proper structural boundary conditions, and accurately measuring applied pressure and transverse displacements simultaneously. In addition to these issues, most previously-developed pressure-bulge instruments rely on vacuum pump loadings. Such tools are limited by the one-atmosphere differential pressure over the membrane, which is inadequate for burst testing of high-strength films. Consequently, an enhanced pressure-bulge tool has been developed and will be described in this paper. It incorporates positive pressure to overcome the one-atmosphere load limitation, improved edge constraints, and the ability to test an array of membrane windows across a single substrate.

scholarly journals Optical and Structural Characterization of Cd-Free Buffer Layers Fabricated by Chemical Bath Deposition

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 897
Author(s):  
William Vallejo ◽  
Carlos Diaz-Uribe ◽  
Cesar Quiñones
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Chemical Bath Deposition ◽  
Structural Characterization ◽  
Optical Transmittance ◽  
Deposition Process ◽  
Buffer Layers ◽  
Visible Range ◽  
Electromagnetic Spectrum ◽  
Distribution Diagram

Chemical bath deposition (CBD) is a suitable, inexpensive, and versatile synthesis technique to fabricate different semiconductors under soft conditions. In this study, we deposited Zn(O;OH)S thin films by the CBD method to analyze the effect of the number of thin film layers on structural and optical properties of buffer layers. Thin films were characterized by X-ray diffraction (XRD) and UV-Vis transmittance measurements. Furthermore, we simulated a species distribution diagram for Zn(O;OH)S film generation during the deposition process. The optical results showed that the number of layers determined the optical transmittance of buffer layers, and that the transmittance reduced from 90% (with one layer) to 50% (with four layers) at the visible range of the electromagnetic spectrum. The structural characterization indicated that the coatings were polycrystalline (α-ZnS and β-Zn(OH)2 to four layers). Our results suggest that Zn(O;OH)S thin films could be used as buffer layers to replace CdS thin films as an optical window in thin-film solar cells.

Processing of Y1Ba2Cu3O7-x Superconducting Thin Films on GaAs Substrates with Double Buffer Layers

1991 ◽  
Vol 236 ◽  
Author(s):  
Sang Yeol Lee ◽  
Quanxi Jia ◽  
Wayne A. Anderson ◽  
David T. Shaw
Keyword(s):  
Thin Films ◽  
Buffer Layer ◽  
Film Deposition ◽  
Buffer Layers ◽  
Deposition Condition ◽  
Gaas Substrates ◽  
Ybco Thin Films ◽  
Layer Deposition ◽  
Zero Resistance

AbstractHigh temperature superconducting Y1Ba2Cu3O7-x(YBCO) thin films have been grown on GaAs substrates by in situ laser deposition with a double buffer layer of yttrium-stabilized ZrO2 (YSZ)/Si3N4. A barrier layer using a combination of YSZ/Si3N4 was used to grow high quality YBCO thin films without the degradation of the GaAs during YBCO film deposition. Strongly c-axis oriented superconducting YBCO thin films with a zero resistance temperature of 85.5 K and a critical current density of 1.9x103 A/cm2 at 77 K have been obtained. The electrical properties of the YBCO thin films were mainly dependent on YSZ buffer layer deposition condition.

scholarly journals Deviation in Nano-Mechanical Properties of Ceramic Nano Composite Thin Films

2017 ◽  
Vol 14 (1) ◽  
pp. 01-04
Author(s):  
A. S. Bhattacharyya ◽  
R. P. Kumar
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Properties ◽  
Magnetron Sputtering ◽  
Strain Hardening ◽  
Hard Coatings ◽  
Film Stress ◽  
Nano Composite ◽  
Thin Film Stress ◽  
Morphological Patterns

Ceramic hard Coatings based on Si, C , N, Ti and B were developed using magnetron sputtering, applicable for protecting the underlying substrate. Different morphological patterns were observed on the coating surface due to sputtering. Nanoindentation was used to determine the hardness and modulus of the coatings. The deviations in H and E values were attributed to indentation positions, thin film stress and anisotropy. Evidence of strain hardening was found during loading.

Stress and Stability of Sputter Deposited A-15 and BCC Crystal Structure Tungsten Thin Films

1997 ◽  
Vol 472 ◽  
Author(s):  
M. J. O'keefe ◽  
C. E. Stutz
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Stress Measurement ◽  
Thermal Studies ◽  
Film Stress ◽  
Thin Film Stress ◽  
Deposition Parameters ◽  
Magnetron Sputter Deposition ◽  
Series Of Experiments ◽  
Sputter Deposited

ABSTRACTMagnetron sputter deposition was used to fabricate body centered cubic (bec) and A-15 crystal structure W thin films. Previous work demonstrated that the as-deposited crystal structure of the films was dependent on the deposition parameters and that the formation of a metastable A-15 structure was favored over the thermodynamically stable bec phase when the films contained a few atomic percent oxygen. However, the A-15 phase was shown to irreversibly transform into the bec phase between 500°C and 650°C and that a significant decrease in the resistivity of the metallic films was measured after the transformation. The current investigation of 150 nm thick, sputter deposited A-15 and bec tungsten thin films on silicon wafers consisted of a series of experiments in which the stress, resistivity and crystal structure of the films was measured as a function of temperature cycles in a Flexus 2900 thin film stress measurement system. The as-deposited film stress was found to be a function of the sputtering pressure and presputter time; under conditions in which the as-deposited stress of the film was ∼ 1.5 GPa compressive delamination of the W film from the substrate was observed. Data from the thermal studies indicated that bec film stress was not affected by annealing but transformation of the A-15 structure resulted in a large tensile increase in the stress of the film, regardless of the as-deposited stress of the film. In several instances, complete transformation of the A-15 structure into the bec phase resulted in ≥ 1 GPa tensile increase in film stress.

Growth, Structure, and Thin Film Stress in TiAl AND Ti3Al FILMS

1993 ◽  
Vol 317 ◽  
Author(s):  
M. Chinmulgund ◽  
R. B. Inturi ◽  
J. A. Barnard
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Properties ◽  
Magnetron Sputtering ◽  
Hexagonal Structure ◽  
Film Stress ◽  
Dc Magnetron Sputtering ◽  
Bulk Materials ◽  
Growth Structure ◽  
Thin Film Stress

ABSTRACTThin films of Ti, Al, TiAl and Ti3Al were deposited by dc magnetron sputtering onto 2” dia. oxidized Si<111> wafers and their mechanical properties were studied by measuring the internal stress in the films. Ti and Ti3Al films show hexagonal structure with preferred orientation in the (0002) direction. TiAl is tetragonal, nanocrystalline, and (111) oriented; Al is random fee polycrystalline in nature. Young's Modulii of thin films of these materials were calculated from the stress temperature plots. The E values of TiAI and Ti3Al thin films were found to be significantly higher than those of the bulk Materials.

Residual Stress Reduction in Sputter Deposited Thin Films by Density Modulation

2009 ◽  
Vol 1224 ◽  
Author(s):  
Arif Sinan Alagoz ◽  
Jan-Dirk Kamminga ◽  
Sergey Yu Grachev ◽  
Toh-Ming Lu ◽  
Tansel Karabacak
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Residual Stress ◽  
Stress Reduction ◽  
Mechanical Stability ◽  
Film Stress ◽  
Radius Of Curvature ◽  
Thin Film Stress ◽  
Order Of Magnitude ◽  
Sputter Deposited

AbstractControl of residual stress in thin films is critical in obtaining high mechanical quality coatings without cracking, buckling, or delamination. In this work, we present a simple and effective method of residual stress reduction in sputter deposited thin films by stacking low and high material density layers of the same material. This multilayer density modulated film is formed by successively changing working gas pressure between high and low values, which results in columnar nanostructured and dense continuous layers, respectively. In order to investigate the evolution of residual stress in density modulated thin films, we deposited ruthenium (Ru) films using a DC magnetron sputtering system at alternating argon (Ar) pressures of 20 and 2 mTorr. Wafer’s radius of curvature was measured to calculate the intrinsic thin film stress of multilayer Ru coatings as a function of total film thickness by changing the number of high density and low density layers. By engineering the film density, we were able to reduce film stress more than one order of magnitude compared to the conventional dense films produced at low working gas pressures. Due to their low stress and enhanced mechanical stability, we were able to grow these density modulated films to much higher thicknesses without suffering from buckling. Morphology and crystal structure of the thin films were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). A previously proposed model for stress reduction by means of relatively rough and compliant sublayers was used to explain the unusually low stress in the specimens investigated.

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