Browsing by Subject "Sputtering"
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Item Open Access Fabrication and characterization of zinc oxide based surface acoustic wave devices(Bilkent University, 2013) Noyan, Mehmet AlicanSurface acoustic wave (SAW) devices, as applied to today’s technology, were first described in 1965. Since then, these devices were applied to a wide variety of fields. Bandpass filter is their most common application, which is an important component in consumer products such as televisions and mobile phones. SAW devices can also be utilized as chemical and biological sensors. Driving force behind the development of SAW sensors is their small size, high sensitivity, reliability, and durability. This thesis presents the development and characterization of ZnO/Si based SAW devices. ZnO thin films with c-axis orientation were deposited using rfmagnetron sputtering. Effect of post deposition annealing on the structure of ZnO and on the SAW device performance was studied. It was found that annealing ZnO above 600o C is detrimental for SAW device performance. Surface roughness of ZnO increases as the annealing temperature increases. In literature, roughness increase is presented as one of the reasons behind device breakdown. This work shows that roughness is not the primary cause for the breakdown. In addition, effect of SiO2 interlayer insertion between ZnO/Si structure on the device performance was examined together with the effect of ZnO thickness.Item Open Access Ta/Si Schottky diodes fabricated by magnetron sputtering technique(2010) Ocak, Y.S.; Genisel, M.F.; Kiliçoǧlu, T.Electrical properties of Ta/n-Si and Ta/p-Si Schottky barrier diodes obtained by sputtering of tantalum (Ta) metal on semiconductors have been investigated. The characteristic parameters of these contacts like barrier height, ideality factor and series resistance have been calculated using current voltage (I-V) measurements. It has seen that the diodes have ideality factors more than unity and the sum of their barrier heights is 1.21 eV which is higher than the band gap of the silicon (1.12 eV). The results have been attributed the effects of inhomogeneities at the interface of the devices and native oxide layer. In addition, the barrier height values determined using capacitance-voltage (C-V) measurements have been compared the ones obtained from I-V measurements. It has seen that the interface states have strong effects on electrical properties of the diodes such as C-V and Rs-V measurements. © 2010 Elsevier Ltd. All rights reserved.Item Embargo The sub-terahertz region absorption of sputter deposited nanoscale TiAlV thin films(Elsevier B.V., 2022-12-05) Öksüzoğlu, Ramis Mustafa; Altan, Hakan; Abdüsselamoğlu, Mehmet Sait; Özkan, Özlem Başak; Bayram, Yasin; Chakar, Erkan SyuleymanAbsorption in the sub-terahertz region in TiAlV thin films with their potential usage in detectors and plasmonic applications is a crucial point for device performance. This work aims to investigate the thickness-dependent evolution of the sub-terahertz region absorption, electrical resistivity in TiAlV thin films deposited by DC magnetron sputtering and to study the structure-property correlation. For structural analyses, X-ray diffraction and transmission electron microscopy techniques have been used. In different deposition conditions, TiAlV thin films indicating the β-Ti phase with anisotropic growth and the hexagonal AlTi3 phase with equiaxial growth have been produced. High resistivity values have been measured in films with the AlTi3 phase. In all TiAlV thin films with different structures, thickness dependent resistivity change in the range 3–23 nm, whereby a strong increase in electrical resistivity with decreasing film thickness have been observed below a thickness of 6 nm. The sub-terahertz absorption increases with increasing film thickness. The highest terahertz region absorption has been found for the films with the β-Ti phase and anisotropic growth also indicating higher electrical conductivity, which favors absorption sensitive applications in the terahertz region. © 2022 Elsevier B.V.