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Description
Semiconductor wafers are analyzed and their total surface energy γT is measured in three components according to the van Oss theory: (1) γLW, surface energy due to Lifshitz-van der Waals forces or dipole interactions, (2) γ+, surface energy due to interactions with electron donors, and (3) γ–, surface energy due to interactions with electron acceptors. Surface energy is measured via Three Liquid Contact Angle Analysis (3LCAA), a method of contact angle measurement using the sessile drop technique and three liquids: water, glycerin, and α-bromonaphthalene. This research optimizes the experimental methods of 3LCAA, proving that the technique produces reproducible measurements for surface energy on a variety of surfaces. Wafer surfaces are prepared via thermal oxidation, rapid thermal oxidation, ion beam oxidation, rapid thermal annealing, hydrofluoric acid etching, the RCA clean, the Herbots-Atluri (H-A) process, and the dry and wet anneals used for Dry and Wet NanoBonding™, respectively.
NanoBonding™ is a process for growing molecular bonds between semiconducting surfaces to create a hermetic seal. NanoBonding™ prevents fluid percolation, protecting integrated electronic sensors from corrosive mobile ion species such as sodium. This can extend the lifetime of marine sensors and glucose sensors from less than one week to over two years, dramatically reducing costs and improving quality of life for diabetic patients. Surface energy measurement is critical to understanding and optimizing NanoBonding™. Surface energies are modified through variations on the H-A process, and measured via 3LCAA. The majority of this research focuses on silicon oxide surfaces.
This is the first quantitative measurement of gallium arsenide surface energy in three components. GaAs is a III-V semiconductor with potential commercial use in transistors, but its oxide layer slowly evaporates over time. In subsequent research, 3LCAA may prove key to developing a stable GaAs oxide layer.
NanoBonding™ is a process for growing molecular bonds between semiconducting surfaces to create a hermetic seal. NanoBonding™ prevents fluid percolation, protecting integrated electronic sensors from corrosive mobile ion species such as sodium. This can extend the lifetime of marine sensors and glucose sensors from less than one week to over two years, dramatically reducing costs and improving quality of life for diabetic patients. Surface energy measurement is critical to understanding and optimizing NanoBonding™. Surface energies are modified through variations on the H-A process, and measured via 3LCAA. The majority of this research focuses on silicon oxide surfaces.
This is the first quantitative measurement of gallium arsenide surface energy in three components. GaAs is a III-V semiconductor with potential commercial use in transistors, but its oxide layer slowly evaporates over time. In subsequent research, 3LCAA may prove key to developing a stable GaAs oxide layer.
ContributorsDavis, Ender (Author) / Herbots, Nicole (Thesis director) / Culbertson, Robert (Committee member) / Watson, Clarizza (Committee member) / Barrett, The Honors College (Contributor)
Created2016-05
Description
This dissertation reports three studies about what it means for teachers and students to reason with frames of reference: to conceptualize a reference frame, to coordinate multiple frames of reference, and to combine multiple frames of reference. Each paper expands on the previous one to illustrate and utilize the construct of frame of reference. The first paper is a theory paper that introduces the mental actions involved in reasoning with frames of reference. The concept of frames of reference, though commonly used in mathematics and physics, is not described cognitively in any literature. The paper offers a theoretical model of mental actions involved in conceptualizing a frame of reference. Additionally, it posits mental actions that are necessary for a student to reason with multiple frames of reference. It also extends the theory of quantitative reasoning with the construct of a ‘framed quantity’. The second paper investigates how two introductory calculus students who participated in teaching experiments reasoned about changes (variations). The data was analyzed to see to what extent each student conceptualized the variations within a conceptualized frame of reference as described in the first paper. The study found that the extent to which each student conceptualized, coordinated, and combined reference frames significantly affected his ability to reason productively about variations and to make sense of his own answers. The paper ends by analyzing 123 calculus students’ written responses to one of the tasks to build hypotheses about how calculus students reason about variations within frames of reference. The third paper reports how U.S. and Korean secondary mathematics teachers reason with frame of reference on open-response items. An assessment with five frame of reference tasks was given to 539 teachers in the US and Korea, and the responses were coded with rubrics intended to categorize responses by the extent to which they demonstrated conceptualized and coordinated frames of reference. The results show that the theory in the first study is useful in analyzing teachers’ reasoning with frames of reference, and that the items and rubrics function as useful tools in investigating teachers’ meanings for quantities within a frame of reference.
ContributorsJoshua, Surani Ashanthi (Author) / Thompson, Patrick W (Thesis advisor) / Carlson, Marilyn (Committee member) / Roh, Kyeong Hah (Committee member) / Middleton, James (Committee member) / Culbertson, Robert (Committee member) / Arizona State University (Publisher)
Created2019