2,383 research outputs found
Empyema necessitans and a persistent air leak associated with rupture of an anaerobic lung abscess due to bacteroides
No abstract available
Analyzing the effects of individual and team attributes on new product design outcomes - Experimental Protocol Development and Feasibility Assessment
Rapidly changing markets demand quick turnaround from creative concepts into final products. This requires firms to have extensive collaboration in their New Product Development (NPD) teams. However effective management of teams can be difficult. In order to understand the challenges of multidisciplinary product development, this study focuses on student design teams conducting engineering design projects at RIT. This study utilizes a modified team effectiveness model based on existing literature for identifying hypothesized associations using a limited number of teams enrolled in senior design. It proposes an experimental protocol for conducting this study at a larger scale and identifies the appropriate tools needed to measure team constructs. The study provides experimental techniques to collect team characteristic data and it also develops techniques to quantify the design process. This study concludes that the experimental protocol is feasible, but that the use of latent semantic analysis is not a feasible approach to measure team mental models at the scale of the size of the MSD program. In addition, a novel method to measure product development project outcomes is proposed that is based on Axiomatic Design principles. Finally, a preliminary assessment of the expected associations suggests that five out of eight propositions behave as predicted by the team effectiveness model; however, the number of project teams used in the study are too small for these results to be conclusive
Spectroscopic ellipsometry for the in-situ investigation of atomic layer depositions
Aim of this student research project was to develop an Aluminium Oxide (Al2O3 ) ALD process from trimethylaluminum (TMA) and Ozone in comparison of two shower head designs. Then studying the detailed characteristics of Al2O3 ALD process using various measurement techniques such as Spectroscopic Ellipsometry (SE), x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM). The real-time ALD growth was studied by in-situ SE. In-situ SE is very promising technique that allows the time-continuous as well as time-discrete measurement of the actual growth over an ALD process time. The following ALD process parameters were varied and their inter-dependencies
were studied in detail: exposure times of precursor and co-reactant as well as Argon purge times, the deposition temperature, total process pressure, flow dynamics of two different shower head designs. The effect of varying these ALD process parameters was studied by looking upon ALD cycle attributes. Various ALD cycle attributes are: TMA molecule adsorption (Mads ), Ligand removal (Lrem ), growth kinetics (KO3 ) and growth per cycle (GPC).:List of abbreviations and Symbols ........................XII
Lists of Figures and Tables ...................................XVIII
1 Introduction .......................................................1
I Theoretical Part ..................................................3
2 Alumina in electronic industry ............................5
3 Atomic Layer Deposition ....................................7
3.1 History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.2 Process definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.3 Benefits and limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.4 ALD growth mechanism of Aluminium oxide from TMA/O 3 . . . . . . . . 9
3.5 Growth kinetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.6 Comparison of TMA/O3 and TMA/H2O – A literature survey . . . . 14
4 Spectroscopic Ellipsometry .....................................................17
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.2 Measuring Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.3 Fitting and models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.4 Advantages and limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5 X-Ray Photoelectron Spectroscopy ..............................................25
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.2 XPS mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.3 XPS analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.4 Advantages and limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
6 Atomic Force Microscopy .............................................................29
II Experimental Part ......................................................................31
7 Methodologies ............................................................................33
7 .1 Experimental setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
7 .2 ALD process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
7 .3 Experiment design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
7 .4 Spectroscopic Ellipsometry . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
7 .4.1 Tool and software . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
7 .4.2 Data acquisition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
7 .4.3 Data evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
7 .4.4 Post processing of data . . . . . . . . . . . . . . . . . . . . . . . . . 41
7 .4.5 Sources of errors in SE . . . . . . . . . . . . . . . . . . . . . . . . . 43
8 Results and discussion ..........................................................47
8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
8.2 Kinetic ALD characteristic curves . . . . . . . . . . . . . . . . . . . . . . . . 48
8.2.1 TMA exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
8.2.2 Argon purging after TMA exposure . . . . . . . . . . . . . . . . . . . 50
8.2.3 Ozone exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
8.2.4 Argon purging after ozone exposure . . . . . . . . . . . . . . . . . . 52
8.3 Impact of process parameters on characteristic ALD growth attributes and film properties . . . . . . . . . .. . . . . . . . . . . . . . . . 53
8.3.1 Total process pressure . . . . . . . . . . . . . . . . . . . . . . . . . . 53
8.3.2 Ozone flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
8.3.3 Deposition temperature . . . . . . . . . . . . . . . . . . . . . . . . . 56
8.4 Reproducibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
9 Conclusions and outlook .......................................................63
References ...............................................................................68
III Appendix .............................................................................77
A Reference temperatures and ozone flow.............................. 79
B Process parameters ..............................................................8
Thermal Atomic Level Etching of Al2O3, HfO2, TiN and SiGe
With a continuous pursuit of making semiconductor devices and integrated
circuits (ICs) faster, better, and more energy efficient, the shrinking of device
dimensions became imminent. Today we are approaching the ångström era,
where the manufacturability of such devices is becoming challenging. As a
result, atomic level processing (ALP) is now most desired. Atomic layer
deposition (ALD) and atomic level etching are two such ALP methods that
take full advantage of surface chemistry and allow growth and removal of
atomistically thin layers of material on a substrate, respectively. Atomic level
etching broadly describes the etching that maintains the ångström-level (i.e.
below 1 nm) etched-thickness control and uses sequential gas-surface
reactions that may be self-limiting. Atomic level etching can be either plasma
based (plasma atomic layer etching - PALE), or thermal based (thermal
atomic layer etching - ALEt, gas-phase pulsed etching - GPPE). PALE has
existed at least for three decades. Although thermal atomic level etching is
relatively new, it has evolved rapidly over the last seven years.
In this thesis work, new thermal atomic level etching processes based on
NbF5 , HF, CCl4 , SOCl2 , O2 , and O3/O2 reactants were developed. The materials that were removed selectively over SiO2 and Si3N4 are Al2O3, TiN, and HfO2 . Two types of etching processes were investigated, the first one uses
sequential exposures of two or more reactants (ALEt), and the second uses
pulsing of a single reactant (GPPE) to etch the target. The processes
explored here show that the novel etch chemistries are capable of removing
the material in the ångström regime isotropically from 3D structures.
Thermochemical analyses of possible reactions based on the atomic-scale
surface-gas models were carried out using first-principles calculations in
density functional theory (DFT) as well as molecular dynamics (MD)
simulations. In addition, potential etch reactions were also evaluated using
conventional thermodynamic calculations. Finally, the post-etched surfaces
were characterized using various surface sensitive techniques such as
spectroscopic ellipsometry (SE), X-ray photoelectron spectroscopy (XPS),
X-ray reflectivity/diffraction (XRR/XRD), transmission electron microscopy
(TEM), atomic force microscopy (AFM), and weighing balance.With a continuous pursuit of making semiconductor devices and integrated
circuits (ICs) faster, better, and more energy efficient, the shrinking of device
dimensions became imminent. Today we are approaching the ångström era,
where the manufacturability of such devices is becoming challenging. As a
result, atomic level processing (ALP) is now most desired. Atomic layer
deposition (ALD) and atomic level etching are two such ALP methods that
take full advantage of surface chemistry and allow growth and removal of
atomistically thin layers of material on a substrate, respectively. Atomic level
etching broadly describes the etching that maintains the ångström-level (i.e.
below 1 nm) etched-thickness control and uses sequential gas-surface
reactions that may be self-limiting. Atomic level etching can be either plasma
based (plasma atomic layer etching - PALE), or thermal based (thermal
atomic layer etching - ALEt, gas-phase pulsed etching - GPPE). PALE has
existed at least for three decades. Although thermal atomic level etching is
relatively new, it has evolved rapidly over the last seven years.
In this thesis work, new thermal atomic level etching processes based on
NbF5 , HF, CCl4 , SOCl2 , O2 , and O3/O2 reactants were developed. The materials that were removed selectively over SiO2 and Si3N4 are Al2O3, TiN, and HfO2 . Two types of etching processes were investigated, the first one uses
sequential exposures of two or more reactants (ALEt), and the second uses
pulsing of a single reactant (GPPE) to etch the target. The processes
explored here show that the novel etch chemistries are capable of removing
the material in the ångström regime isotropically from 3D structures.
Thermochemical analyses of possible reactions based on the atomic-scale
surface-gas models were carried out using first-principles calculations in
density functional theory (DFT) as well as molecular dynamics (MD)
simulations. In addition, potential etch reactions were also evaluated using
conventional thermodynamic calculations. Finally, the post-etched surfaces
were characterized using various surface sensitive techniques such as
spectroscopic ellipsometry (SE), X-ray photoelectron spectroscopy (XPS),
X-ray reflectivity/diffraction (XRR/XRD), transmission electron microscopy
(TEM), atomic force microscopy (AFM), and weighing balance
Evaluation of novel metalorganic precursors for atomic layer deposition of Nickel-based thin films
Nickel und Nickel (II) -oxid werden in großem Umfang in fortgeschrittenen elektronischen Geräten verwendet. In der Mikroelektronik-Industrie wird Nickel verwendet werden, um Nickelsilizid bilden. Die Nickelmono Silizid (NiSi) wurde als ausgezeichnetes Material für Source-Drain-Kontaktanwendungen unter 45 nm-CMOS-Technologie entwickelt. Im Vergleich zu anderen Siliziden für die Kontaktanwendungen verwendet wird NiSi wegen seines niedrigen spezifischen Widerstand, niedrigen Kontaktwiderstand, relativ niedrigen Bildungstemperatur und niedrigem Siliziumverbrauchs bevorzugt. Nickel in Nickelbasis-Akkus und ferromagnetischen Direktzugriffsspeicher (RAMs) verwendet. Nickel (II) oxid wird als Transistor-Gate-Oxid und Oxid in resistive RAM genutzt wird.
Atomic Layer Deposition (ALD) ist eine spezielle Art der Chemical Vapor Deposition (CVD), das verwendet wird, um sehr glatte sowie homogene Dünnfilme mit hervorragenden Treue auch bei hohen Seitenverhältnissen abzuscheiden. Es basiert auf selbstabschließenden sequentielle Gas-Feststoff-Reaktionen, die eine präzise Steuerung der Filmdicke auf wenige Angström lassen sich auf der Basis. Zur Herstellung der heutigen 3D-elektronische Geräte, sind Technologien wie ALD erforderlich. Trotz der Vielzahl von praktischen Anwendungen von Nickel und Nickel (II) -oxid, sind einige Nickelvorstufen zur thermischen basierend ALD erhältlich.
Darüber hinaus haben diese Vorstufen bei schlechten Filmeigenschaften führte und die Prozesseigenschaften wurden ebenfalls begrenzt. Daher in dieser Masterarbeit mussten die Eigenschaften verschiedener neuartiger Nickelvorstufen zu bewerten. Alle neuen Vorstufen heteroleptische (verschiedene Arten von Liganden) und Komplexe wurden vom Hersteller speziell zur thermischen basierend ALD aus reinem Nickel mit H 2 als ein Co-Reaktionsmittel gestaltet. Um die neuartige Vorläufer zu untersuchen, wurde eine neue Methode entwickelt, um kleine Mengen in einer sehr zeitsparend (bis zu 2 g) von Ausgangsstoffen zu testen. Diese Methodologie beinhaltet: TGA / DTA-Kurve analysiert der Vorstufen, thermische Stabilitätstests in dem die Vorläufer (<0,1 g) wurden bei erhöhter Temperatur in einer abgedichteten Umgebung für mehrere Stunden wurde die Abscheidung Experimenten und Film Charakterisierungen erhitzt. Die Abscheidungen wurden mit Hilfe der in situ Quarzmikrowaage überwacht, während die anwendungsbezogenen Filmeigenschaften, wie chemische Zusammensetzung, physikalische Phase, Dicke, Dichte, Härte und Schichtwiderstand wurden mit Hilfe von ex situ Messverfahren untersucht.
Vor der Evaluierung neuartiger Nickelvorstufen ein Benchmark ALD-Prozess war vom Referenznickelvorläufer (Ni (AMD)) und Luft als Reaktionspartner entwickelt. Das Hauptziel der Entwicklung und Optimierung von solchen Benchmark-ALD-Prozess war es, Standard-Prozessparameter wie zweite Reaktionspartner Belichtungszeiten, Argonspülung Zeiten, gesamtprozessdruck, beginnend Abscheidungstemperatur und Gasströme zu extrahieren. Diese Standard-Prozessparameter mussten verwendet, um die Prozessentwicklung Aufgabe (das spart Vorläufer Verbrauch) zu verkürzen und die Sublimationstemperatur Optimierung für jede neuartige Vorstufe werden. Die ALD Verhalten wurde in Bezug auf die Wachstumsrate durch Variation des Nickelvorläuferbelichtungszeit, Vorläufer Temperatur und Niederschlagstemperatur überprüft.:Lists of Abbreviations and Symbols VIII
Lists of Figures and Tables XIV
1 Introduction 1
I Theoretical Part 3
2 Nickel and Nickel Oxides 4
2.1 Introduction and Existence 5
2.2 Material properties of Nickel and Nickel Oxide 5
2.3 Application in electronic industry 5
3 Atomic Layer Deposition 7
3.1 History 8
3.2 Definition 8
3.3 Features of thermal-ALD 8
3.3.1 ALD growth mechanism – an ideal view 8
3.3.2 ALD growth behaviour 10
3.3.3 Growth mode 11
3.3.4 ALD temperature window 11
3.4 Benefits and limitations 12
3.5 Precursor properties for thermal-ALD 13
3.6 ALD & CVD of Nickel – A literature survey 13
4 Metrology 17
4.1 Thermal analysis of precursors 18
4.2 Film and growth characterization 21
4.2.1 Quartz Crystal Microbalance 21
4.2.2 Spectroscopic Ellipsometry 24
4.2.3 X-Ray Photoelectron Spectroscopy 28
4.2.4 Scanning Electron Microscopy 29
4.2.5 X-Ray Reflectometry and X-Ray Diffraction 29
4.2.6 Four Point Probe Technique 20
5 Rapid Thermal Processing 32
5.1 Introduction 33
5.2 Basics of RTP 33
5.3 Nickel Silicides-A literature survey 33
II Experimental Part 36
6 Methodologies 37
6.1 Experimental setup 38
6.2 ALD process 41
6.2.1 ALD process types and substrate setups 41
6.2.2 Process parameters 41
6.3 Experimental procedure 42
6.3.1 Tool preparation 42
6.3.2 Thermal analysis and ALD experiments from nickel precursors 43
6.3.3 Data acquisition and evaluation 44
6.3.4 Characterization of film properties 46
7 Results and discussion 48
7.1 Introduction 49
7.2 QCM verification with Aluminum Oxide ALD process 49
7.3 ALD process from the reference precursor 50
7.3.1 Introduction 50
7.3.2 TG analysis for Ni(amd) precursor 51
7.3.3 Thermal stability test for Ni(amd) 51
7.3.4 ALD process optimization 52
7.3.5 Film properties 54
7.4 Evaluating the novel Nickel precursors 55
7.4.1 Screening tests for precursor P1 55
7.4.2 Screening tests for precursor P2 62
7.4.3 Screening tests for precursor P3 66
7.4.4 Screening tests for precursor P4 70
7.4.5 Screening tests for precursor P5 72
7.5 Comparison of all nickel precursors used in this work 74
8 Conclusions and outlook 77
References 83
III Appendix 101
A Deposition temperature control & Ellipsometry model 102
B Gas flow plan 105Nickel and nickel(II) oxide are widely used in advanced electronic devices . In microelectronic industry, nickel is used to form nickel silicide. The nickel mono-silicide (NiSi) has emerged as an excellent material of choice for source-drain contact applications below 45 nm node CMOS technology. As compared to other silicides used for the contact applications, NiSi is preferred because of its low resistivity, low contact resistance, relatively low formation temperature and low silicon consumption. Nickel is used in nickel-based rechargeable batteries and ferromagnetic random access memories (RAMs). Nickel(II) oxide is utilized as transistor gate-oxide and oxide in resistive RAMs.
Atomic Layer Deposition (ALD) is a special type of Chemical Vapor Deposition (CVD) technique, that is used to deposit very smooth as well as homogeneous thin films with excellent conformality even at high aspect ratios. It is based on self-terminating sequential gas-solid reactions that allow a precise control of film thickness down to few Angstroms. In order to fabricate todays 3D electronic devices, technologies like ALD are required.
In spite of huge number of practical applications of nickel and nickel(II) oxide, a few nickel precursors are available for thermal based ALD. Moreover, these precursors have resulted in poor film qualities and the process properties were also limited. Therefore in this master thesis, the properties of various novel nickel precursors had to be evaluated. All novel precursors are heteroleptic (different types of ligands) complexes and were specially designed by the manufacturer for thermal based ALD of pure nickel with H 2 as a co-reactant.
In order to evaluate the novel precursors, a new methodology was designed to test small amounts (down to 2 g) of precursors in a very time efficient way. This methodology includes: TGA/DTA curve analyses of the precursors, thermal stability tests in which the precursors (< 0.1 g) were heated at elevated temperatures in a sealed environment for several hours, deposition experiments, and film characterizations. The depositions were monitored with the help of in situ quartz crystal microbalance, while application related film properties like chemical composition, physical phase, thickness, density, roughness and sheet resistance were investigated with the help of ex situ measurement techniques.
Prior to the evaluation of novel nickel precursors, a benchmark ALD process was developed from the reference nickel precursor (Ni(amd)) and air as a co-reactant. The main goal of developing and optimizing such benchmark ALD process was to extract standard process parameters like second-reactant exposure times, Argon purge times, total process pressure, starting deposition temperature and gas flows. These standard process parameters had to be utilized to shorten the process development task (thus saving precursor consumption) and optimize the sublimation temperature for each novel precursor. The ALD behaviour was checked in terms of growth rate by varying the nickel precursor exposure time, precursor temperature and deposition temperature.:Lists of Abbreviations and Symbols VIII
Lists of Figures and Tables XIV
1 Introduction 1
I Theoretical Part 3
2 Nickel and Nickel Oxides 4
2.1 Introduction and Existence 5
2.2 Material properties of Nickel and Nickel Oxide 5
2.3 Application in electronic industry 5
3 Atomic Layer Deposition 7
3.1 History 8
3.2 Definition 8
3.3 Features of thermal-ALD 8
3.3.1 ALD growth mechanism – an ideal view 8
3.3.2 ALD growth behaviour 10
3.3.3 Growth mode 11
3.3.4 ALD temperature window 11
3.4 Benefits and limitations 12
3.5 Precursor properties for thermal-ALD 13
3.6 ALD & CVD of Nickel – A literature survey 13
4 Metrology 17
4.1 Thermal analysis of precursors 18
4.2 Film and growth characterization 21
4.2.1 Quartz Crystal Microbalance 21
4.2.2 Spectroscopic Ellipsometry 24
4.2.3 X-Ray Photoelectron Spectroscopy 28
4.2.4 Scanning Electron Microscopy 29
4.2.5 X-Ray Reflectometry and X-Ray Diffraction 29
4.2.6 Four Point Probe Technique 20
5 Rapid Thermal Processing 32
5.1 Introduction 33
5.2 Basics of RTP 33
5.3 Nickel Silicides-A literature survey 33
II Experimental Part 36
6 Methodologies 37
6.1 Experimental setup 38
6.2 ALD process 41
6.2.1 ALD process types and substrate setups 41
6.2.2 Process parameters 41
6.3 Experimental procedure 42
6.3.1 Tool preparation 42
6.3.2 Thermal analysis and ALD experiments from nickel precursors 43
6.3.3 Data acquisition and evaluation 44
6.3.4 Characterization of film properties 46
7 Results and discussion 48
7.1 Introduction 49
7.2 QCM verification with Aluminum Oxide ALD process 49
7.3 ALD process from the reference precursor 50
7.3.1 Introduction 50
7.3.2 TG analysis for Ni(amd) precursor 51
7.3.3 Thermal stability test for Ni(amd) 51
7.3.4 ALD process optimization 52
7.3.5 Film properties 54
7.4 Evaluating the novel Nickel precursors 55
7.4.1 Screening tests for precursor P1 55
7.4.2 Screening tests for precursor P2 62
7.4.3 Screening tests for precursor P3 66
7.4.4 Screening tests for precursor P4 70
7.4.5 Screening tests for precursor P5 72
7.5 Comparison of all nickel precursors used in this work 74
8 Conclusions and outlook 77
References 83
III Appendix 101
A Deposition temperature control & Ellipsometry model 102
B Gas flow plan 10
Categorizing Software Regression Test Results
Customer complaints in cloud computing can originate from components of the cloud infrastructure platform or from components of third-party software. Further, cloud infrastructure components causing issues can affect customers generally or only customers under certain computing environments or using certain third-party software. Pinpointing the origin of a given customer complaint using targeted testing of components in isolation is computationally infeasible. This disclosure describes techniques that correlate test signals across multiple sources to reliably categorize issues in cloud computing to identify the origin of bad rollouts in a timely and cost-efficient manner. An issue that affects a plurality of workloads can cause test signals generated by the workloads to become correlated. By discovering correlations between signals emitted by distinct workloads, determination can be made of the workloads, customer subsets, computing environments, and third-party software impacted by the issue
Automatically Identifying Regression Detection Conditions for System Performance Metrics
System performance in various computing systems is measured using various benchmarks. A benchmark allows users to observe a set of performance metrics of the system as a function of time and workload, and to determine if a performance metric has deviated or regressed. However, different regression analyzers are suitable for different metrics and finding accurate analyzers often requires substantial manual effort that needs to be repeated whenever a variable that impacts a performance metric changes. This disclosure describes techniques that obtain historical data (sourced from stable workloads) about the pattern of a performance metric and use the data to train a machine learning algorithm to analyze a performance metric and determine a suitable analyzer. The analyzer configuration is selected based upon classification of the metric as noisy or not noisy, and on what is suitable for the particular metric
UTILIZING USER-LEVEL SIGNALS FOR EARLY SPAM PROCESSING
A mechanism for early detection of a spam item by utilizing user-level signals associated with the user uploading the content item in advance of spending significant resources on processing the content item is disclosed. Upon detection of initiation of a content item uploaded by a user on a content item service, user-level signals associated with the user uploading the content item may be retrieved. Based on the user-level signals, it may be determined that the content item is a likely spam item. Subsequently, limited processing maybe performed by converting the content item may into a single file and content analysis may be performed on the single file. Based on the content analysis, it may be determined that the content item is an actual spam item and the availability of the content item may be restricted on the content item service
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