David W Parent
Other affiliations: University of California, Santa Cruz, University of Connecticut
Bio: David W Parent is an academic researcher from San Jose State University. The author has contributed to research in topic(s): Transistor & Metalorganic vapour phase epitaxy. The author has an hindex of 8, co-authored 53 publication(s) receiving 299 citation(s). Previous affiliations of David W Parent include University of California, Santa Cruz & University of Connecticut.
Papers published on a yearly basis
TL;DR: In this article, the authors show that threading dislocations can be removed from patterned heteroepitaxial semiconductors by glide to the sidewalls, which is driven by the presence of image forces.
Abstract: We have shown that threading dislocations can be removed from patterned heteroepitaxial semiconductors by glide to the sidewalls, which is driven by the presence of image forces. In principle, it should be possible to attain highly mismatched heteroepitaxial semiconductors which are completely free from threading dislocations, even though they are not pseudomorphic, by patterned heteroepitaxial processing. There are two basic approaches to patterned heteroepitaxial processing. The first involves selective area growth on a pre-patterned substrate. The second approach involves post-growth patterning followed by annealing. We have developed a quantitative model which predicts that there is a maximum lateral dimension for complete removal of threading dislocations by patterned heteroepitaxy. According to our model, this maximum lateral dimension is proportional to the layer thickness and increases monotonically with the lattice mismatch. For heteroepitaxial materials with greater than 1% lattice mismatch, our model predicts that practical device-sized threading dislocation-free regions may be realized by patterned heteroepitaxial processing.
19 Jan 2013-SpringerPlus
TL;DR: In this paper, the authors explored correlations between team outcomes, personality measures and ability in an undergraduate population, and found that personality, in terms of extraversion scores, was positively correlated with instructors' assessment of team performance, which is consistent with prior research.
Abstract: The ability to work effectively on a team is highly valued by employers, and collaboration among students can lead to intrinsic motivation, increased persistence, and greater transferability of skills. Moreover, innovation often arises from multidisciplinary teamwork. The influence of personality and ability on undergraduate teamwork and performance is not comprehensively understood. An investigation was undertaken to explore correlations between team outcomes, personality measures and ability in an undergraduate population. Team outcomes included various self-, peer- and instructor ratings of skills, performance, and experience. Personality measures and ability involved the Five-Factor Model personality traits and GPA. Personality, GPA, and teamwork survey data, as well as instructor evaluations were collected from upper division team project courses in engineering, business, political science, and industrial design at a large public university. Characteristics of a multidisciplinary student team project were briefly examined. Personality, in terms of extraversion scores, was positively correlated with instructors’ assessment of team performance in terms of oral and written presentation scores, which is consistent with prior research. Other correlations to instructor-, students’ self- and peer-ratings were revealed and merit further study. The findings in this study can be used to understand important influences on successful teamwork, teamwork instruction and intervention and to understand the design of effective curricula in this area moving forward.
TL;DR: In this article, a comparison of x-ray diffraction methods for the determination of the critical layer thickness for dislocation multiplication in mismatched heteroepitaxy was presented.
Abstract: We present a comparison of x-ray diffraction methods for the determination of the critical layer thickness for dislocation multiplication in mismatched heteroepitaxy. The conventional x-ray diffraction method for determination of the critical layer thickness is based on the direct observation of the lattice relaxation in measurements of strain (the “strain method”). An indirect method is based on the observation of the x-ray rocking curve broadening by the threading dislocations, which are introduced concurrently with misfit dislocations (the “full width at half maximum (FWHM) method”). For this study, we have applied both methods to ZnSe grown on GaAs (001) by metalorganic vapor phase epitaxy (MOVPE). We have compared the resolution of the two x-ray diffraction methods both theoretically and experimentally for the case of 004 reflections using Cukα1 radiation. Theoretically, we have shown that in this case the FWHM method is 2.6 times more sensitive to relaxation than the strain method. This conclusion is supported by our experiments, in which we determined a critical layer thickness value of 140 nm by the FWHM method, compared to 210 nm as determined by the strain method.
TL;DR: Improvements made to a complimentary metal-oxide-semiconductor fabrication laboratory course to increase student learning and student impact (enrollment).
Abstract: This paper presents improvements made to a complimentary metal-oxide-semiconductor (CMOS) fabrication laboratory course to increase student learning and student impact (enrollment). The three main improvements to the course discussed include: 1) use of a two-mask MOS process that significantly reduced the time students took previously to design, fabricate, and verify the electrical properties of a metal-oxide-semiconductor field-effect transistor (MOSFET) process; 2) students' use of a semicustom integrated circuit (IC) design that significantly reduced the average design and processing time of previous years; and 3) development and implementation of a system of course prerequisites, which allowed a larger number of students to enroll in the course.
TL;DR: For ternary heteroepitaxial layers, the independent determination of the composition and state of strain requires x-ray rocking curve measurements for at least two different hkl reflections as discussed by the authors.
Abstract: For ternary heteroepitaxial layers, the independent determination of the composition and state of strain requires x-ray rocking curve measurements for at least two different hkl reflections because the relaxed lattice constant is a function of the composition. The usual approach involves the use of one symmetric reflection and one asymmetric reflection. Two rocking curves are measured at opposing azimuths for each hkl reflection. Thus, it is possible to account for tilting of the hkl planes in the epitaxial layer with respect to the hkl planes in the substrate, by averaging the peak separations obtained at the opposing azimuths. This procedure presents a practical problem in the case of asymmetric reflections, for which the tilting can only be canceled if the rocking curve for one azimuth is obtained using θ−φ incidence. A preferable approach, which provides sharper, more intense rocking curves and greater experimental accuracy, is to measure both asymmetric rocking curves at θ+φ incidence. This approach ...
TL;DR: This book by a teacher of statistics (as well as a consultant for "experimenters") is a comprehensive study of the philosophical background for the statistical design of experiment.
Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON
TL;DR: An exhaustive review of the research conducted in neuromorphic computing since the inception of the term is provided to motivate further work by illuminating gaps in the field where new research is needed.
Abstract: Neuromorphic computing has come to refer to a variety of brain-inspired computers, devices, and models that contrast the pervasive von Neumann computer architecture This biologically inspired approach has created highly connected synthetic neurons and synapses that can be used to model neuroscience theories as well as solve challenging machine learning problems The promise of the technology is to create a brain-like ability to learn and adapt, but the technical challenges are significant, starting with an accurate neuroscience model of how the brain works, to finding materials and engineering breakthroughs to build devices to support these models, to creating a programming framework so the systems can learn, to creating applications with brain-like capabilities In this work, we provide a comprehensive survey of the research and motivations for neuromorphic computing over its history We begin with a 35-year review of the motivations and drivers of neuromorphic computing, then look at the major research areas of the field, which we define as neuro-inspired models, algorithms and learning approaches, hardware and devices, supporting systems, and finally applications We conclude with a broad discussion on the major research topics that need to be addressed in the coming years to see the promise of neuromorphic computing fulfilled The goals of this work are to provide an exhaustive review of the research conducted in neuromorphic computing since the inception of the term, and to motivate further work by illuminating gaps in the field where new research is needed
17 May 2006
TL;DR: In this paper, the fabrication of monolithic lattice-mismatched semiconductor heterostructures with limited area regions having upper portions substantially exhausted of threading dislocations is discussed.
Abstract: Fabrication of monolithic lattice-mismatched semiconductor heterostructures with limited area regions having upper portions substantially exhausted of threading dislocations, as well as fabrication of semiconductor devices based on such lattice-mismatched heterostructures.
02 Feb 2007-Applied Physics Letters
TL;DR: In this article, a defect-free germanium was demonstrated in SiO2 trenches on silicon via aspect ratio trapping, whereby defects arising from lattice mismatch are trapped by laterally confining sidewalls.
Abstract: Defect-free germanium has been demonstrated in SiO2 trenches on silicon via Aspect Ratio Trapping, whereby defects arising from lattice mismatch are trapped by laterally confining sidewalls. Results were achieved through a combination of conventional photolithography, reactive ion etching of SiO2, and selective growth of Ge as thin as 450nm. Full trapping of dislocations originating at the Ge∕Si interface has been demonstrated for trenches up to 400nm wide without the additional formation of defects at the sidewalls. This approach shows great promise for the integration of Ge and/or III-V materials, sufficiently large for key device applications, onto silicon substrates.