Current Search: Thin film (x)
Pages
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Title
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X-ray Scattering Investigations of Metallic Thin Films.
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Creator
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Warren, Andrew, Coffey, Kevin, Sohn, Yongho, Suryanarayana, Challapalli, Heinrich, Helge, Barmak, Katayun, Toney, Michael, University of Central Florida
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Abstract / Description
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Nanometric thin films are used widely throughout various industries and for various applications. Metallic thin films, specifically, are relied upon extensively in the microelectronics industry, among others. For example, alloy thin films are being investigated for CMOS applications, tungsten films find uses as contacts and diffusion barriers, and copper is used often as interconnect material. Appropriate metrology methods must therefore be used to characterize the physical properties of...
Show moreNanometric thin films are used widely throughout various industries and for various applications. Metallic thin films, specifically, are relied upon extensively in the microelectronics industry, among others. For example, alloy thin films are being investigated for CMOS applications, tungsten films find uses as contacts and diffusion barriers, and copper is used often as interconnect material. Appropriate metrology methods must therefore be used to characterize the physical properties of these films. X-ray scattering experiments are well suited for the investigation of nano-scaled systems, and are the focus of this doctoral dissertation. Emphasis is placed on (1) phase identification of polycrystalline thin films, (2) the evaluation of the grain size and microstrain of metallic thin films by line profile analysis, and (3) the study of morphological evolution in solid/solid interfaces.To illustrate the continued relevance of x-ray diffraction for phase identification of simple binary alloy systems, Pt-Ru thin films, spanning the compositional range from pure Pt to pure Ru were investigated. In these experiments, a meta-stable extension of the HCP phase is observed in which the steepest change in the electronic work function coincides with a rapid change in the c/a ratio of the HCP phase.For grain size and microstrain analysis, established line profile methods are discussed in terms of Cu and W thin film analysis. Grain sizes obtained by x-ray diffraction are compared to transmission electron microscopy based analyses. Significant discrepancies between x-ray and electron microscopy are attributed to sub-grain misorientations arising from dislocation core spreading at the film/substrate interface. A novel "residual" full width half max parameter is introduced for examining the contribution of strain to x-ray peak broadening. The residual width is subsequently used to propose an empirical method of line profile analysis for thin films on substrates.X-ray reflectivity was used to study the evolution of interface roughness with annealing for a series of Cu thin films that were encapsulated in both SiO2 and Ta/SiO2. While all samples follow similar growth dynamics, notable differences in the roughness evolution with high temperature ex-situ annealing were observed. The annealing resulted in a smoothing of only one interface for the SiO2 encapsulated films, while neither interface of the Ta/SiO2 encapsulated films evolved significantly. The fact that only the upper Cu/SiO2 interface evolves is attributed to mechanical pinning of the lower interface to the rigid substrate. The lack of evolution of the Cu/Ta/SiO2 interface is consistent with the lower diffusivity expected of Cu in a Cu/Ta interface as compared to that in a Cu/SiO2 interface. The smoothing of the upper Cu/SiO2 interface qualitatively follows that expected for capillarity driven surface diffusion but with notable quantitative deviation.
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Date Issued
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2013
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Identifier
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CFE0004770, ucf:49784
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0004770
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Title
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Deposition and characterization studies of boron carbon nitride (BCN) thin films prepared by dual target sputtering.
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Creator
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Prakash, Adithya, Sundaram, Kalpathy, Kapoor, Vikram, Yuan, Jiann-Shiun, Jin, Yier, Chow, Louis, University of Central Florida
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Abstract / Description
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As complementary metal-oxide semiconductor (CMOS) devices shrink to smaller size, the problems related to circuit performance such as critical path signal delay are becoming a pressing issue. These delays are a result of resistance and capacitance product (RC time constant) of the interconnect circuit. A novel material with reduced dielectric constants may compromise both the thermal and mechanical properties that can lead to die cracking during package and other reliability issues. Boron...
Show moreAs complementary metal-oxide semiconductor (CMOS) devices shrink to smaller size, the problems related to circuit performance such as critical path signal delay are becoming a pressing issue. These delays are a result of resistance and capacitance product (RC time constant) of the interconnect circuit. A novel material with reduced dielectric constants may compromise both the thermal and mechanical properties that can lead to die cracking during package and other reliability issues. Boron carbon nitride (BCN) compounds have been expected to combine the excellent properties of boron carbide (B4C), boron nitride (BN) and carbon nitride (C3N4), with their properties adjustable, depending on composition and structure. BCN thin film is a good candidate for being hard, dense, pore-free, low-k dielectric with values in the range of 1.9 to 2.1. Excellent mechanical properties such as adhesion, high hardness and good wear resistance have been reported in the case of sputtered BCN thin films. Problems posed by high hardness materials such as diamonds in high cutting applications and the comparatively lower hardness of c-BN gave rise to the idea of a mixed phase that can overcome these problems with a minimum compromise in its properties. A hybrid between semi-metallic graphite and insulating h-BN may show adjusted semiconductor properties. BCN exhibits the potential to control optical bandgap (band gap engineering) by atomic composition, hence making it a good candidate for electronic and photonic devices. Due to tremendous bandgap engineering capability and refractive index variability in BCN thin film, it is feasible to develop filters and mirrors for use in ultra violet (UV) wavelength region. It is of prime importance to understand process integration challenges like deposition rates, curing, and etching, cleaning and polishing during characterization of low-k films. The sputtering technique provides unique advantages over other techniques such as freedom to choose the substrate material and a uniform deposition over relatively large area. BCN films are prepared by dual target reactive magnetron sputtering from a B4C and BN targets using DC and RF powers respectively. In this work, an investigation of mechanical, optical, chemical, surface and device characterizations is undertaken. These holistic and thorough studies, will provide the insight into the capability of BCN being a hard, chemically inert, low-k, wideband gap material, as a potential leader in semiconductor and optics industry.
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Date Issued
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2016
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Identifier
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CFE0006378, ucf:51496
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0006378
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