Compliant Substrate Processes

1999 ◽  
Vol 570 ◽  
Author(s):  
W. A. Doolittle ◽  
A. S. Brown
Keyword(s):  
Defect Density ◽  
Coefficient Of Thermal Expansion ◽  
Growth Dynamics ◽  
Bonding Layer ◽  
New Approach ◽  
Compliant Substrate ◽  
Compliant Substrates ◽  
Potential Applications ◽  
Processing Effects ◽  
Lithium Gallate

ABSTRACTRecent results indicate that compliant substrates offer significant promise as a new approach for strain management in semiconductors. The potential applications include 1) the growth of device-quality highly mismatched materials on dissimilar substrates, and 2) the lateral control of material properties resulting from the effects of strain on bandstructure and/or growth dynamics. A significant amount of research in this area is dedicated to the reduction of extrinsic processing effects resulting from compliant substrate fabrication, and the development of simple models for understanding the observed reduction in defect density and/or strain in the epitaxial films grown on compliant substrates. A recent focus in our work has been on the growth of GaN on a novel and easily removable substrate -lithium gallate- for the regrowth on a bonded GaN template. The first step in this approach is the optimization of the growth of GaN on lithium gallate. In addition, this approach requires the use of an appropriate bonding layer to reduce the strain or defect production during growth due to coefficient of thermal expansion mismatches between the GaN sample and the handle wafer. Our work in this area will be highlighted in the context of an overview of various compliant substrate approaches and current results that indicate their efficacy.

An in situ and ex situ TEM study of the formation of thin cobalt silicide films by molecular beam epitaxy on the silicon (100) surface

1988 ◽  
Vol 46 ◽  
pp. 884-885
Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove ◽  
R. T. Tung
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Defect Density ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Metal Base ◽  
In Situ Experiments ◽  
Potential Applications

The cobalt disilicide/silicon system has potential applications as a metal-base and as a permeable-base transistor. Although thin, low defect density, films of CoSi2 on Si(111) have been successfully grown, there are reasons to believe that Si(100)/CoSi2 may be better suited to the transmission of electrons at the silicon/silicide interface than Si(111)/CoSi2. A TEM study of the formation of CoSi2 on Si(100) is therefore being conducted. We have previously reported TEM observations on Si(111)/CoSi2 grown both in situ, in an ultra high vacuum (UHV) TEM and ex situ, in a conventional Molecular Beam Epitaxy system.The procedures used for the MBE growth have been described elsewhere. In situ experiments were performed in a JEOL 200CX electron microscope, extensively modified to give a vacuum of better than 10-9 T in the specimen region and the capacity to do in situ sample heating and deposition. Cobalt was deposited onto clean Si(100) samples by thermal evaporation from cobalt-coated Ta filaments.

Hot-Wire CVD Poly-Silicon Films for Thin Film Devices

1998 ◽  
Vol 507 ◽  
Author(s):  
J.K. Rath ◽  
F.D. Tichelaar ◽  
H. Meiling ◽  
R.E.I. Schropp
Keyword(s):  
Defect Density ◽  
Initial Growth ◽  
Oriented Growth ◽  
Compact Structure ◽  
High Hydrogen ◽  
New Approach ◽  
Intrinsic Nature ◽  
Bias Stress ◽  
Hydrogen Dilution ◽  
Long Duration

ABSTRACTSolar cell using profiled poly-Si:H by HWCVD as i-layer in the configuration SS/n-µSi:H(PECVD)/i-poly-Si:H(HWCVD)/p-µc-Si:H(PECVD)/ITO showed 3.7% efficiency. A current of 23.6 mA/cm2 was generated in only 1.5 µm thick poly-Si:H i-layer grown at ∼5Å/s. TFTs made with the poly-Si:H films (grown at ≥ 9Å/s) exhibited remarkable stability to long duration of 23 hours of gate bias stress of ∼lMV/cm. A saturation mobility of 1.5 cm2/Vs for the TFT has been achieved. Films made at low hydrogen dilution (Poly2) showed device quality (purely intrinsic nature, ambipolar diffusion length of 568 nm, only (220) oriented growth and low ESR defect density of <1017/cm3with complete absence of signal due to conduction electrons) but with an incubation phase of amorphous initial growth, whereas the films made at high hydrogen dilution (Polyl) had a polycrystalline initial growth, though with higher defect density, incorporated oxygen and randomly oriented grains. Poly2 films are compact and hydrogen bonding is at compact Si-H sites manifested as 2000 cm−1IR vibration and high temperature hydrogen evolution peak. Exchange interaction of spins and spin pairing are observed while increasing defects in such a compact structure. A new approach has been used to integrate these two regimes of growth to make profiled poly-Si:H layers. The new layers show good electronic properties as well as complete elimination of incubation phase.

A new approach to characterization of the transition temperatures of thin film NiTi shape memory alloys

2004 ◽  
Vol 19 (6) ◽  
pp. 1762-1767
Author(s):  
Nicholas W. Botterill ◽  
David M. Grant ◽  
Jianxin Zhang ◽  
Clive J. Roberts
Keyword(s):  
Thin Film ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Transition Temperatures ◽  
New Approach ◽  
Novel Approach ◽  
Potential Applications ◽  
Niti Shape Memory Alloys

A novel approach in determining the transition temperatures of NiTi shape memory alloys was investigated and compared with conventional techniques. The technique is based on microthemal analysis using a scanning thermal microscope (SThM). In particular, this method has the potential to allow the transformation temperatures of thin films to be investigated in situ. Thin film shape memory alloys have potential applications, such as microactuators, where conventional analysis techniques are either not directly applicable to such samples or are difficult to perform.

Bulk Gan Crystal With Low Defect Density Grown By Hydride Vapor Phase Epitaxy

1997 ◽  
Vol 482 ◽  
Author(s):  
A. Usui
Keyword(s):  
Vapor Phase ◽  
Flat Surface ◽  
Defect Density ◽  
Vapor Phase Epitaxy ◽  
Hydride Vapor Phase Epitaxy ◽  
Extended Defect ◽  
New Approach ◽  
Bulk Gan ◽  
Gan Crystal ◽  
Reflectance Measurements

AbstractA new approach to grow thick GaN layers by hydride vapor phase epitaxy (HVPE) is described. Selective growth is carried out at the beginning of growth. The coalescence of selectively grown facet structures makes it possible to achieve a flat surface over the entire substrate. As a result, crack-free GaN films with mirror-like surfaces are successfully grown even to a thickness of about 100 μm on a 2-inch-diameter sapphire substrate. The extended defect density is as low as 6×107 cm−2. The reduction mechanism for dislocation is discussed based on TEM observation. The high optical properties of FIELO GaN are confirmed by 5 K photoluminescence and reflectance measurements.

Compliant Substrates for Reduction of Strain Relief in Mismatched Overlayers

1996 ◽  
Vol 441 ◽  
Author(s):  
Carrie Carter-Coman ◽  
Robert Bicknell-Tassius ◽  
April S. Brown ◽  
Nan Marie Jokerst
Keyword(s):  
Thin Film ◽  
Variable Thickness ◽  
Critical Thickness ◽  
Strain Relief ◽  
Compliant Substrate ◽  
Compliant Substrates ◽  
Experimental Strain

AbstractThin film compliant substrates can be used to extend the critical thickness in mismatched overlayers. A metastability model has been coupled with recent experimental strain relief data to determine the critical thickness of InGaAs epilayers grown on GaAs compliant substrates of variable thickness. The results of this model are also compared to other compliant substrate critical thickness models.

Porous functions

2019 ◽  
Vol 22 (6) ◽  
pp. 1502-1516 ◽  
Author(s):  
Igor Podlubny
Keyword(s):  
Geometric Structure ◽  
General Concept ◽  
New Approach ◽  
Potential Applications ◽  
New Type

Abstract A new approach to modeling the geometric structure of real materials based on a new type of functions – porous functions – is introduced. The general concept, basic operations, operations of calculus, visualization and interpretations, and potential applications of porous functions are outlined.

The Defence by Design framework: Conceptual foundations and potential applications

2021 ◽  
Vol 7 (2) ◽  
pp. 211-232 ◽  
Author(s):  
Cara Wrigley ◽  
Harjit Rana ◽  
Peta Hinton ◽  
Genevieve Mosely
Keyword(s):  
Design Thinking ◽  
Value Added ◽  
Design Framework ◽  
New Approach ◽  
A Value ◽  
Potential Applications ◽  
Defence Strategy ◽  
Military Objective ◽  
Conceptual Foundations

With rapid advancements in technology radically impacting and changing current ways of working globally, many industries and sectors, including the Defence force, are implementing new approaches to respond to and address these challenges. Design thinking is one approach to assist in this response, as it provides a novel process for solving complex problems. This article presents a specific design approach for addressing contextual Defence problems in the form of a design thinking framework based on a review of the existing literature concerning design and Defence. The article contends with the role of design as a value-added methodology in Defence strategy and development, and it reports on a unique set of design thinking capabilities for a Defence-specific context that are not only essential for the implementation of a design-led approach to innovation but are of great assistance in overcoming its associated challenges. The Defence by Design framework works with an identified military objective that, when applied, overcomes the natural bias that Defence personnel may exhibit during routine gaps and opportunities analysis. By detailing the different stages of the framework, and demonstrating their iterative nature, through the documentation of a working example – ‘Man Overboard’ – this article presents a new approach yet to be realized in Defence globally.

On cost-aware biased respondent group selection for minority opinion survey

2016 ◽  
Vol 08 (04) ◽  
pp. 1650061
Author(s):  
Wei Wang ◽  
Donghyun Kim ◽  
Matthew Tetteh ◽  
Jun Liang ◽  
Wonjun Lee
Keyword(s):  
Social Relation ◽  
Survey Respondent ◽  
New Approach ◽  
Limited Budget ◽  
Polynomial Time Algorithms ◽  
Wide Range ◽  
Respondent Group ◽  
Potential Applications ◽  
Representative Selection ◽  
Relation Graph

This paper discusses a new approach to use a specially constructed social relation graph with high homophily to select a survey respondent group under a limited budget such that the result of the survey is biased to the minority opinions. This approach has a wide range of potential applications, e.g., collecting diversified complaints from the customers while most of them are satisfied, but is hardly investigated. We formulate the problem of computing such a group as the [Formula: see text]-biased-representative selection problem ([Formula: see text]-BRSP), where [Formula: see text] represents the size of the group constraint by the available budget. This problem has two independent optimization goals and therefore is difficult to deal with. We introduce two polynomial time algorithms for the problem, where each of which has an approximation ratio with respect to each of the objectives when the other optimization objective is substituted with a constraint. Under the substituted constraint, we prove that the first algorithm is an [Formula: see text]-approximation (which is best possible) algorithm with respect to the first objective and the second algorithm is a 2-approximation (which is best possible) with respect to the second objective, where [Formula: see text] is the degree of the input social relation graph.

Characterization of Chemically Vapor Deposited GaN on Sic on a Simox Substrate

1997 ◽  
Vol 3 (S2) ◽  
pp. 487-488
Author(s):  
W.L. Zhou ◽  
P. Pirouz
Keyword(s):  
Lattice Mismatch ◽  
Defect Density ◽  
Silicon Layer ◽  
Large Defect ◽  
Cross Sectional ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Transmission Electron ◽  
Potential Applications ◽  
Gan Film

GaN has been intensively studied because of its potential applications for the fabrication of blue- or ultraviolet-light emitting devices. Sapphire (α-Al2O3) is generally used as the substrate for growth of GaN film. However, the large lattice mismatch between GaN and Al2O3is a possible cause of the large defect density in the GaN films. Consequently, alternative substrates are being studied with the aim of growing films of lesser defect densities and improved opto-electronic properties. In this paper, we report a transmission electron microscopy (TEM) study of a GaN film grown on cubic SiC which has been obtained by carbonization of the top silicon layer of a SIMOX substrate, i.e. the system GaN/SiC/Si/SiO2/Si.Cross-sectional TEM specimens were prepared by the conventional sandwich technique with the foil surface normal to the Si[l10] direction. The composite sample was ground and dimpled to a thickness of ∼ 10μm, and subsequently ion thinned to electron transparency.

Thermal properties of nanocrystalline Al composites reinforced by AlN nanoparticles

2009 ◽  
Vol 24 (1) ◽  
pp. 24-31 ◽  
Author(s):  
Y.Q. Liu ◽  
H.T. Cong ◽  
H.M. Cheng
Keyword(s):  
Thermal Properties ◽  
Room Temperature ◽  
Significant Contribution ◽  
Elevated Temperatures ◽  
Volume Fraction ◽  
Coefficient Of Thermal Expansion ◽  
High Tc ◽  
Percolation Behavior ◽  
Potential Applications ◽  
Electronic Packaging Material

To explore potential applications of nanocomposites for microelectronic packaging, the thermal properties were investigated on newly developed nanocrystalline Al composites reinforced by AlN nanoparticles. It was found that the thermal conductivity (TC) is reduced with increasing AlN volume fraction (Vp), since connectivity of Al matrix is decreased by introduction of the nanoparticles. Although AlN nanoparticles introduce thermal resistance, they still have significant contribution to the TC of the composite as high-TC inclusion. Particularly, a percolation behavior of AlN nanoparticles is thought to occur with the threshold at 23–30%. Measurements at elevated temperatures (∼500 °C) show almost no distinct degradation of TC relative to room temperature. Moreover, the coefficient of thermal expansion (CTE) is remarkably lowered as Vp increases, e.g., from 26 × 10−6 to 13.9 × 10−6 K−1, by raising Vp to 39%. Therefore, the nanocomposites may be applicable as electronic packaging material, due to the combination of acceptable TC and low CTE.

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