Jaime MoyaMajor: Engineering Physics Mentor: Dr. Stefan Zollner, Academic Department HeadPhysics at New Mexico State University
I am a proud native New Mexican who is expected to graduate with a bachelor’s degree in engineering physics in the Spring of 2017. After graduation, I plan to attend graduate school. I am currently applying to graduate schools in both engineering and physics. In engineering, I am interested in the field of fluid dynamics. As for physics, I am interested in materials. I am excited to evaluate my options, and see where life takes me. My goal is to eventually use my degrees to bridge the gap between science and technology.
I am grateful for the opportunity to participate in the New Mexico AMP Undergraduate Research Scholars Program for the Summer of 2015 through the Fall of 2016. During my time in the program, I have learned about characterization techniques for materials, including taking x-ray reflectivity, x-ray diffraction, atomic force microscopy, and ellipsometry measurements as well, as analyzing the data.
Aside from school, I am the vice-president of the Aerospace Honors Society, Sigma Gamma Tau. On my spare time, I enjoy a nice bike ride through the pecan orchards, brewing a batch of home-brewed beer, and collecting baseball memorabilia.
FTIR Ellipsometry Studies of Thermally Grown GeO2 on Ge
To study the vibrational modes of GeO2, we produced a set of thermal GeO2 oxides ranging from 45 to 136 nm in thickness. Receiving a set of Ge Bulk wafers, we cleaved and roughened the back sides via an aluminum abrasive to avoid backside reflections. To remove carbon-containing surface contaminants and leave a stable oxide on the wafer, we performed a hybrid dry/wet clean. The dry clean was done by subjecting the wafer to an ozone clean in an ultrapure oxygen environment while heating the sample to 150°C for 1 hour, followed by a 30 minute incubation period. The samples were then cleaned ultrasonically for 20 minutes in deionized water followed by 20 minutes in isopropanol. No harsh chemicals were used. The samples were then dried with nitrogen and annealed at 270 kPa and 550°C in ultrapure oxygen for a few hours to achieve different oxide thicknesses.
Using Fourier-transform infrared ellipsometry, the ellipsometric angles ψ and Δ were measured from 250 to 6000cm-1 at several angles of incidence (60° to 75°). The infrared lattice absorption peak of the amorphous GeO2 was fit with a Lorentz oscillator.
When comparing our results to Lippincott’s et al.  transmission measurements of vitreous GeO2 formed by quenching hexagonal GeO2, we see a negative shift in vibrational frequency. The difference can be attributed to the different Ge-O bond length comparing the vitreous GeO2 and our amorphous thermal oxide. Our amorphous thermal oxide GeO2 samples have a longer bond length, corresponding to a weaker bond and a lower vibrational frequency. This shift also shows a lower density of our samples compared to Lippincott et al .
 E.R. Lippincott, A. Van Valkenburg, C.E. Weir, and E.N. Bunting, J. Res. Natl. Bur. Stand. 61, 61 (1958).