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- Creators: Barrett, The Honors College
- Creators: McCartney, Martha R.
Description
This paper goes does a market analysis on Inter Active Flat Panel Displays (IFPDs), and talks about how company X can grow its market share in IFPDs.
ContributorsKoroli, Eri (Co-author) / Phillips, Maya (Co-author) / Morales, Herwin (Co-author) / Hauck, Tanner (Co-author) / Simonson, Mark (Thesis director) / Hertzel, Michael (Committee member) / School of Accountancy (Contributor) / Department of Finance (Contributor) / Department of Information Systems (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
The research of this dissertation involved quantitative characterization of electrostatic potential and charge distribution of semiconductor nanostructures using off-axis electron holography, as well as other electron microscopy techniques. The investigated nanostructures included Ge quantum dots, Ge/Si core/shell nanowires, and polytype heterostructures in ZnSe nanobelts. Hole densities were calculated for the first two systems, and the spontaneous polarization for wurtzite ZnSe was determined. Epitaxial Ge quantum dots (QDs) embedded in boron-doped silicon were studied. Reconstructed phase images showed extra phase shifts near the base of the QDs, which was attributed to hole accumulation in these regions. The resulting charge density was (0.03±0.003) holes
m3, which corresponded to about 30 holes localized to a pyramidal, 25-nm-wide Ge QD. This value was in reasonable agreement with the average number of holes confined to each Ge dot determined using a capacitance-voltage measurement. Hole accumulation in Ge/Si core/shell nanowires was observed and quantified using off-axis electron holography and other electron microscopy techniques. High-angle annular-dark-field scanning transmission electron microscopy images and electron holograms were obtained from specific nanowires. The intensities of the former were utilized to calculate the projected thicknesses for both the Ge core and the Si shell. The excess phase shifts measured by electron holography across the nanowires indicated the presence of holes inside the Ge cores. The hole density in the core regions was calculated to be (0.4±0.2)
m3 based on a simplified coaxial cylindrical model. Homogeneous zincblende/wurtzite heterostructure junctions in ZnSe nanobelts were studied. The observed electrostatic fields and charge accumulation were attributed to spontaneous polarization present in the wurtzite regions since the contributions from piezoelectric polarization were shown to be insignificant based on geometric phase analysis. The spontaneous polarization for the wurtzite ZnSe was calculated to be psp = -(0.0029±0.00013) C/m2, whereas a first principles' calculation gave psp = -0.0063 C/m2. The atomic arrangements and polarity continuity at the zincblende/wurtzite interface were determined through aberration-corrected high-angle annular-dark-field imaging, which revealed no polarity reversal across the interface. Overall, the successful outcomes of these studies confirmed the capability of off-axis electron holography to provide quantitative electrostatic information for nanostructured materials.
m3, which corresponded to about 30 holes localized to a pyramidal, 25-nm-wide Ge QD. This value was in reasonable agreement with the average number of holes confined to each Ge dot determined using a capacitance-voltage measurement. Hole accumulation in Ge/Si core/shell nanowires was observed and quantified using off-axis electron holography and other electron microscopy techniques. High-angle annular-dark-field scanning transmission electron microscopy images and electron holograms were obtained from specific nanowires. The intensities of the former were utilized to calculate the projected thicknesses for both the Ge core and the Si shell. The excess phase shifts measured by electron holography across the nanowires indicated the presence of holes inside the Ge cores. The hole density in the core regions was calculated to be (0.4±0.2)
m3 based on a simplified coaxial cylindrical model. Homogeneous zincblende/wurtzite heterostructure junctions in ZnSe nanobelts were studied. The observed electrostatic fields and charge accumulation were attributed to spontaneous polarization present in the wurtzite regions since the contributions from piezoelectric polarization were shown to be insignificant based on geometric phase analysis. The spontaneous polarization for the wurtzite ZnSe was calculated to be psp = -(0.0029±0.00013) C/m2, whereas a first principles' calculation gave psp = -0.0063 C/m2. The atomic arrangements and polarity continuity at the zincblende/wurtzite interface were determined through aberration-corrected high-angle annular-dark-field imaging, which revealed no polarity reversal across the interface. Overall, the successful outcomes of these studies confirmed the capability of off-axis electron holography to provide quantitative electrostatic information for nanostructured materials.
ContributorsLi, Luying (Author) / McCartney, Martha R. (Thesis advisor) / Smith, David J. (Thesis advisor) / Treacy, Michael J. (Committee member) / Shumway, John (Committee member) / Drucker, Jeffery (Committee member) / Arizona State University (Publisher)
Created2011
Description
Due to the high level of competition within the semiconductor industry, companies are looking to identify potential advantages in their manufacturing processes. This paper attempts to discover when it is more cost effective to disaggregate die versus maintaining a monolithic production process. Additionally, it will examine the current conditions of the market and how the results yielded from the research could be applied most effectively. Company X needs to maintain the same or more cores on their processors to stay ahead of their competition. This means that more surface area is needed on the silicon die, encouraging the change to die disaggregation and advanced packaging solutions. In the paper, we will first provide an analysis and go through our two cost equations for monolithic and disaggregated die. We will then break down each part of our cost equations and each variable that goes into it by doing a sensitivity analysis. The sensitivity analysis will give us some insight into which variables are affecting our cost equation the most, and thus which variables Company X should pay the most attention to while deciding whether or not to continue to use the monolithic die or move to the disaggregated process. Based on our findings we came to the conclusion that Company X should continue to utilize a monolithic die for all mobile products. However, all desktop and server products should start to consider utilizing a disaggregated die on a case by case basis while examining the specific factors in the cost equation.
ContributorsKuebler, Mason (Author) / Simonson, Mark (Thesis director) / Llazani, Loris (Committee member) / Department of Finance (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
The purpose of this research is to optically characterize germanium-based chalcogenide thin films and evaluate how their properties change when the composition is altered. The composition changes based on if the chalcogenide contains selenium or sulfur, if the film is 60 nanometers or 200 nanometers, and if the film is doped with silver (ranging from 0 nanometers to 30 nanometers). These amorphous germanium-chalcogenide thin films exhibit interesting properties when doped with silver, such as transporting ions within the film in addition to electron transport. Using optical characterization techniques such as UV-Vis spectroscopy, profilometry, and ellipsometry, parameters that describe the optical characteristics are found, including the absorption coefficient, refractive index, optical band gap energy, and information on the density of states. This research concludes that as silver content within the film increases, the optical bandgap energy decreases—this is a consistent trend in existing literature. Having a better understanding of the materials’ physical properties will be useful to aid in the creation of microsystems based on these materials by selecting optimal composition and growth conditions. Important applications using these materials are currently being researched, including variable capacitor devices relying on the ionic conductor behavior these materials display. The optical properties like the absorption coefficient and the optical bandgap energy are invaluable in designing these applications effectively.
ContributorsRicks, Amberly Frances (Author) / Gonzalez Velo, Yago (Thesis director) / Kozicki, Michael (Committee member) / Holman, Zachary (Committee member) / Electrical Engineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
The investigation into wide band gap semiconductors for use in tandem solar cells has become an increasingly more researched area with many new absorbers outlining the landscape. Pairing silicon with another cheap wide band gap semiconductor absorber can generate more efficient solar cell, which could continue to drive up the energy output from solar. One such recently researched wide band gap absorber is ZnSnN2. ZnSnN2 proves too difficult to form under most conditions, but has the necessary band gap to make it a potential earth abundant solar absorber. The deposition process for ZnSnN2 is usually conducted with Zn and Sn metal targets while flowing N2 gas. Due to restrictions with chamber depositions, instead ZnO and SnO2 targets were sputtered with N2 gas to attempt to form separate zinc and tin oxynitrides as an initial single target study prior to future combinatorial studies. The electrical and optical properties and crystal structure of these thin films were analyzed to determine the nitrogen incorporation in the thin films through X-ray diffraction, UV-Vis spectrophotometry, and 4-point probe measurements. The SnO2 thin films showed a clear response in the absorption coefficient leading but showed no observable XRD peak shift. Thus, it is unlikely that substantial amounts of nitrogen were incorporated into SnO¬2. ZnO showed a clear response increase in conductivity with N2 with an additional shift in the XRD peak at 300 °C and potential secondary phase peak. Nitrogen incorporation was achieved with fair amounts of certainty for the ZnO thin films.
ContributorsTheut, Nicholas C (Author) / Bertoni, Mariana (Thesis director) / Holman, Zachary (Committee member) / Materials Science and Engineering Program (Contributor) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
This thesis discusses the yield analysis process for determining the efficacy of experimental changes to a semiconductor manufacturing line, specifically within the chemical mechanical planarization department. Three yield analysis projects were analyzed and related to relevant literature to determine how the changes might impact overall semiconductor yield.
ContributorsRichards, Andrew (Author) / Machas, Michael (Thesis director) / Maguregui, Edgar (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor)
Created2023-05
Description
This paper serves as an analysis of the current operational conditions of a real-world company – referred to as “Company X” – with respect to the IC substrate industry. The cost of substrates, a crucial component in the production of Company X’s product, has recently diverged from Company X’s predictions and is contributing to declining profitability. This analysis aims to discover the underlying cause for price divergence and recommend potential resolutions to improve the forecast of substrate costs and profitability. The paper is organized as follows: Chapter 1 is an introduction to IC substrates and the industry as a whole, Chapter 2 is a breakdown of the specific factors responsible for substrate prices, and Chapter 3 delivers a final recommendation to Company X and concludes the paper.
ContributorsO'Loughlin, Connor (Author) / Fares, Ari (Co-author) / Aggarwal, Bianca (Co-author) / King, Camden (Co-author) / Guillaume, Riley (Co-author) / Simonson, Mark (Thesis director) / Hertzel, Mike (Committee member) / Barrett, The Honors College (Contributor) / Department of Finance (Contributor) / School of Mathematical and Statistical Sciences (Contributor)
Created2023-05
Description
In this dissertation research, conventional and aberration-corrected (AC) transmission electron microscopy (TEM) techniques were used to evaluate the structural and compositional properties of thin-film semiconductor compounds/alloys grown by molecular beam epitaxy for infrared photo-detection. Imaging, diffraction and spectroscopy techniques were applied to TEM specimens in cross-section geometry to extract information about extended structural defects, chemical homogeneity and interface abruptness. The materials investigated included InAs1-xBix alloys grown on GaSb (001) substrates, InAs/InAs1-xSbx type-II superlattices grown on GaSb (001) substrates, and CdTe-based thin-film structures grown on InSb (001) substrates.
The InAsBi dilute-bismide epitaxial films were grown on GaSb (001) substrates at relatively low growth temperatures. The films were mostly free of extended defects, as observed in diffraction-contrast images, but the incorporation of bismuth was not homogeneous, as manifested by the lateral Bi-composition modulation and Bi-rich surface droplets. Successful Bi incorporation into the InAs matrix was confirmed using lattice expansion measurements obtained from misfit strain analysis of high-resolution TEM (HREM) images.
Analysis of averaged intensity line profiles in HREM and scanning TEM (STEM) images of the Ga-free InAs/InAs1-xSbx type-II strained superlattices indicated slight variations in layer thickness across the superlattice stack. The interface abruptness was evaluated using misfit strain analysis of AC-STEM images, electron energy-loss spectroscopy and 002 dark-field imaging. The compositional profiles of antimony across the superlattices were fitted to a segregation model and revealed a strong antimony segregation probability.
The CdTe/MgxCd1-xTe double-heterostructures were grown with Cd overflux in a dual-chamber molecular beam epitaxy with an ultra-high vacuum transfer loadlock. Diffraction-contrast images showed that the growth temperature had a strong impact on the structural quality of the epilayers. Very abrupt CdTe/InSb interfaces were obtained for epilayers grown at the optimum temperature of 265 °C, and high-resolution imaging using AC-STEM revealed an interfacial transition region with a width of a few monolayers and smaller lattice spacing than either CdTe or InSb.
The InAsBi dilute-bismide epitaxial films were grown on GaSb (001) substrates at relatively low growth temperatures. The films were mostly free of extended defects, as observed in diffraction-contrast images, but the incorporation of bismuth was not homogeneous, as manifested by the lateral Bi-composition modulation and Bi-rich surface droplets. Successful Bi incorporation into the InAs matrix was confirmed using lattice expansion measurements obtained from misfit strain analysis of high-resolution TEM (HREM) images.
Analysis of averaged intensity line profiles in HREM and scanning TEM (STEM) images of the Ga-free InAs/InAs1-xSbx type-II strained superlattices indicated slight variations in layer thickness across the superlattice stack. The interface abruptness was evaluated using misfit strain analysis of AC-STEM images, electron energy-loss spectroscopy and 002 dark-field imaging. The compositional profiles of antimony across the superlattices were fitted to a segregation model and revealed a strong antimony segregation probability.
The CdTe/MgxCd1-xTe double-heterostructures were grown with Cd overflux in a dual-chamber molecular beam epitaxy with an ultra-high vacuum transfer loadlock. Diffraction-contrast images showed that the growth temperature had a strong impact on the structural quality of the epilayers. Very abrupt CdTe/InSb interfaces were obtained for epilayers grown at the optimum temperature of 265 °C, and high-resolution imaging using AC-STEM revealed an interfacial transition region with a width of a few monolayers and smaller lattice spacing than either CdTe or InSb.
ContributorsLu, Jing (Author) / Smith, David J. (Thesis advisor) / Alford, Terry L. (Committee member) / Crozier, Peter A. (Committee member) / McCartney, Martha R. (Committee member) / Zhang, Yong-Hang (Committee member) / Arizona State University (Publisher)
Created2017
Description
The research of this dissertation has primarily involved using transmission electron microscopy (TEM) techniques to study several semiconductor materials considered promising for future photovoltaic device applications.
Layers of gallium phosphide (GaP) grown on silicon (Si) substrates were characterized by TEM and aberration-corrected scanning transmission electron microscopy (AC-STEM). High defect densities were observed for samples with GaP layer thicknesses 250nm and above. Anti-phase boundaries (APBs) within the GaP layers were observed at interfaces with the Si surfaces which were neither atomically flat nor abrupt, contradicting conventional understanding of APB formation.
Microcrystalline-Si (μc-Si) layers grown on crystalline-Si (c-Si) substrates were investigated. Without nanoparticle seeding, an undesired amorphous-Si (a-Si) layer grew below the μc-Si layer. With seeding, the undesired a-Si layer grew above the μc-Si layer, but μc-Si growth proceeded immediately at the c-Si surface. Ellipsometry measurements of percent crystallinity did not match TEM images, but qualitative agreement was found between TEM results and Ultraviolet Raman spectroscopy.
TEM and Xray spectroscopy were used to study metal-induced crystallization and layer exchange for aluminum/ germanium (Al/Ge). Only two samples definitively exhibited both Ge crystallization and layer exchange, and neither process was complete in either sample. The results were finally considered as inconclusive since no reliable path towards layer exchange and crystallization was established.
Plan-view TEM images of indium arsenide (InAs) quantum dots with gallium arsenide antimonide (GaAsSb) spacer layers revealed the termination of some threading dislocations in a sample with spacer-layer thicknesses of 2nm, while a sample with 15-nm-thick spacer layers showed a dense, cross-hatched pattern. Cross-sectional TEM images of samples with 5-nm and 10-nm spacer-layer thicknesses showed less layer undulation in the latter sample. These observations supported photoluminescence (PL) and Xray diffraction (XRD) results, which indicated that GaAsSb spacer layers with 10-nm thickness yielded the highest quality material for photovoltaic device applications.
a-Si/c-Si samples treated by hydrogen plasma were investigated using high-resolution TEM. No obvious structural differences were observed that would account for the large differences measured in minority carrier lifetimes. This key result suggested that other factors such as point defects, hydrogen content, or interface charge must be affecting the lifetimes.
Layers of gallium phosphide (GaP) grown on silicon (Si) substrates were characterized by TEM and aberration-corrected scanning transmission electron microscopy (AC-STEM). High defect densities were observed for samples with GaP layer thicknesses 250nm and above. Anti-phase boundaries (APBs) within the GaP layers were observed at interfaces with the Si surfaces which were neither atomically flat nor abrupt, contradicting conventional understanding of APB formation.
Microcrystalline-Si (μc-Si) layers grown on crystalline-Si (c-Si) substrates were investigated. Without nanoparticle seeding, an undesired amorphous-Si (a-Si) layer grew below the μc-Si layer. With seeding, the undesired a-Si layer grew above the μc-Si layer, but μc-Si growth proceeded immediately at the c-Si surface. Ellipsometry measurements of percent crystallinity did not match TEM images, but qualitative agreement was found between TEM results and Ultraviolet Raman spectroscopy.
TEM and Xray spectroscopy were used to study metal-induced crystallization and layer exchange for aluminum/ germanium (Al/Ge). Only two samples definitively exhibited both Ge crystallization and layer exchange, and neither process was complete in either sample. The results were finally considered as inconclusive since no reliable path towards layer exchange and crystallization was established.
Plan-view TEM images of indium arsenide (InAs) quantum dots with gallium arsenide antimonide (GaAsSb) spacer layers revealed the termination of some threading dislocations in a sample with spacer-layer thicknesses of 2nm, while a sample with 15-nm-thick spacer layers showed a dense, cross-hatched pattern. Cross-sectional TEM images of samples with 5-nm and 10-nm spacer-layer thicknesses showed less layer undulation in the latter sample. These observations supported photoluminescence (PL) and Xray diffraction (XRD) results, which indicated that GaAsSb spacer layers with 10-nm thickness yielded the highest quality material for photovoltaic device applications.
a-Si/c-Si samples treated by hydrogen plasma were investigated using high-resolution TEM. No obvious structural differences were observed that would account for the large differences measured in minority carrier lifetimes. This key result suggested that other factors such as point defects, hydrogen content, or interface charge must be affecting the lifetimes.
ContributorsBoley, Allison (Author) / Smith, David J. (Thesis advisor) / McCartney, Martha R. (Thesis advisor) / Liu, Jingyue (Committee member) / Bennett, Peter (Committee member) / Arizona State University (Publisher)
Created2020
Description
The rapid expansion of artificial intelligence has propelled significant growth in the GPU market. In the evolving data center landscape, Company X faces challenges due to its lag in entering the GPU market, which jeopardizes its competitive advantage against industry players like Nvidia and AMD. To address these issues, our thesis aims to analyze market dynamics between CPUs and GPUs-whether they present distinct markets or compete against each other. We seek to guide Company X in maximizing profitability and sustaining its pivotal role in the semiconductor industry amidst the AI revolution. Specifically, we discuss optimizing their GPU offering, Falcon Shores, towards specific markets and doubling down on the production of CPUs.
ContributorsLivesay, Thomas (Author) / Kujawa, Brennan (Co-author) / Ulreich-Power, Cameron (Co-author) / Mostaghimi, Dunya (Co-author) / Simonson, Mark (Thesis director) / Hertzel, Mike (Committee member) / Barrett, The Honors College (Contributor) / Department of Finance (Contributor)
Created2024-05