Abstract AlN thin films grown on Si¡BGlass¡BSiO2 and Si3N4 substrate by RF magnetron sputtering technique with AlN target has been studied.Room temperature growth was applied to this study.During thin film growing, sputtering work pressure, sputtering power, sputtering working distance and sputtering time are those key parameters to be adjusted in order to highly C-axis prefer orientation AlN thin films. The microstructures of the AlN films were examined by x-ray diffraction. TEM was adopted to observe grain growth of the AlN films. The results was compared with the results of reactive RF magnetron sputtering. The results of the X-ray patterns showed that the strong C-axis prefer orientation of the AlN films were obtained with AlN target. in a 17¢Q long sputtering working distance condition, chemical composition of substrate can help to growth of AlN films. The column structures of AlN films can be observed by TEM.

Transparent conductive aluminum-doped zinc oxide(AZO) thin films were synthesized by reactive RF magnetron co-sputtering system with metallic zinc and aluminum targets under oxygen atmosphere. Systematic study on the fixed sputtering power of the Zinc target (PZn) and the variation of the sputtering power of the Aluminum target (PAl) on structural, electrical and optical properties of AZO thin film was mainly investigated in this work. We found that the microstructure of AZO films would be obviously transformed from rice-like crystalline structure to nanocrystalline (nano-column) structure with the increasing of the sputtering power of the Aluminum target (PAl) . Nanocrystalline AZO films were formed at the specific sputtering power ratio of metallic targets (PAl/ PZn=1) . X-ray diffraction (XRD) spectra revealed that nanocrystalline AZO films highly preferred c-axis orientation (002) was growth in perpendicular to the substrate. The optical refractive index (n) of nanocrystalline AZO films had significantly lower values than others of microstructure AZO films, and this suggested the low optical dispersion in nano-column structure . Furthermore, the electronic properties of AZO films with the proper sputtering power of the Aluminum target (PAl) evidently improved under rapid temperature annealing (RTA) process. It suggested that both high annealing temperature(400¢J) and rapid cooling time(15min) are main factors to decrease the sheet resistances due to the maintenance of high temperature structural phase. The results of X-ray photoelectron spectroscopy (XPS) show that RTA process can decrease oxidized Al in order to decrease the sheet resistances.

Reactive Sputtering is a widely used technique in processing of thin compound films. Such films can be sputtered from metal targets, which are comparatively cost efficient. Also the fact that sputtering from metal targets can ccur in the dc mode reduces the cost of the sputtering equipment. To keep the deposition process stable, its necessary to know the effects of target poisoning including its hyteresis behavior. The aim of this work was to nvestigate the evolution of reactive gas coverage on a titanium magnetron target surface, by real time, in-situ ion beam analysis during magnetron sputtering. A cylindrical 2 inch magnetron was used for reactive sputtering of TiN. It was operated in an Ar/N2 gas mixture at achamber pressure of about 3∙10-3 mbar. The argon/nitrogen flux ratio was variated between 0 and 20%. The nitrogen concentration on the target was determinated using the 14N(d, α)12C, nuclear reaction at a deuterium beam energy of 1.8 MeV. Depending on the adjusted nitrogen flow the target incorporation varies between 0 and about 1∙1016 N∙cm-2. Further the expected hysteresis behaviour ofnitrogen partial pressure, target voltage and nitrogen concentration at increasing/decreasing nitrogen gas flow is confirmed. The lateral distribution of nitrogen was measured across the diameter of target surface. In the zone of higher erosion (the \"race track\") the nitrogen concentration is 50% lower than in the middle or the edge of the target. A deposition zone in the center of the target could not be detected. By increasing the nitrogen flow into the chamber a saturation in nitrogen content in the target was found at an Ar/N2 flow ratio of about 10%. Assuming nitrogen implantation with a depth of 2.5 nm under the influence of typical target voltage during magnetron sputtering, this saturation is at a concentration value where stoichiomtric TiN is formed. Within the precision of the measurements, a mobile fraction of nitrogen could not determined. The concentration in the target remains unchanged after switching off the magnetron.

Filmes finos de nitreto de silício com excesso de nitrogênio foram depositados sobre silício por sputtering reativo para obter estruturas emissoras de luz. As amostras foram modificadas por implantação iônica para verificar a influência dos dopantes arsênio (As) e boro (B) nos espectros de fotoluminescência (PL). As medidas de PL foram realizadas na faixa de temperatura entre 15-300 K e apresentaram uma emissão entre os comprimentos de onda 370-870 nm. Os dopantes introduziram uma emissão em 725 nm na banda de emissão, principalmente as dopadas com As. Foram realizadas medidas de microscopias para verificar a presença de nanoestruturas assim como a distribuição dos dopantes no material. As imagens de microscopias confirmaram a presença de nanocristais de nitreto de silício nas fases α, β e γ e identificaram a presença do dopante B nas fases cristalinas. O modelo de condução de Pool-Frenkel domina o transporte de portadores, indicando que a condução ocorre pelos níveis intrabandas, característica que definiu o modo que as recombinações radiativas ocorreram. As medidas de eletroluminescência (EL) apresentaram uma emissão centrada nos comprimentos de onda 760 e 880 nm (polarização negativa) e 1010 nm (polarização positiva) revelando diferenças significativas quando comparadas com as medidas de PL. Essa diferença esta associada à maneira como os elétrons populam os níveis intrabanda (excitação óptica para PL e elétrica para EL) que resulta em recombinações radiativas em diferentes comprimentos de ondas. A intensidade dos espectros de EL manifestou uma dependência quase linear com a densidade de corrente para ambas as polarizações. As medidas de EL em campos alternados exibiram um espectro de emissão composto pela soma das bandas obtidas separadamente em cada uma das polarizações. Medidas de EL em diferentes temperaturas (50-300 K) foram realizadas para investigar a influência da temperatura nos processos de recombinação radiativa. A intensidade exibiu uma redução com o aumento da temperatura, devido ao aumento do acoplamento elétron-fônon. / Silicon nitride with excess of nitrogen thin films were deposited on silicon substrate by reactive sputtering in order to obtain light emitting structures. Samples were modified by ion implantation of arsenic (As) and boron (B) to ascertain dopant leverage at photoluminescence (PL) spectra. PL measurements were performed at temperature ranging from 15 K up to 300 K and showed a band emission between wavelength 370 and 870 nm. An emission centered at 725 nm was observed in doped samples; especially in the presence of As. Microscope images showed crystalline structures of α-Si3N4, β-Si3N4 and γ-Si3N4 and confirmed boron dopant in nanocrystalline structures. Pool-Frenkel conduction model dominates electron transport in non-stoichiometric silicon nitride films due to intraband levels, phenomenon that has a huge contribution to electroluminescence (EL) emission. EL signals were composed by two peaks centered at 760 and 880 nm (negative bias – EL-N) and one peak at 1010 nm (positive bias – EL-P). Diffences between PL and EL spectra exhibit a clear dependence on the mode of excitation (photo and current source) on radiative recombination process. EL intensity had almost a linear increase with current density for both polarizations. EL measurements under AC voltage were composed by a superposition of the signals from EL-N and EL-P signals. Photo and electroluminescence measurements were collected at different temperatures (50 to 300 K) in order to investigate the temperature influence on the radiative recombination. The EL intensity was decreasing with temperature increasing, due to electron-phonon interactions.

This thesis explores the feasibility of high power impulse magnetron sputtering (HiPIMS) to synthesize hydrogenated amorphous carbon (a-C:H) thin films in Ar-hydrocarbon ambient and the relationship between process parameters, gas phase composition and film properties. To this purpose a stable process based on HiPIMS and direct current magnetron sputtering (DCMS) has been developed. Four series of amorphous carbon thin films were deposited by hybrid HiPIMS-DCMS and pure DCMS processes at 15 mTorr pressure using different Ar-acetylene compositions and a substrate bias from 0 to -350 V. The effect of Ar-acetylene compositions and depositions processes on the film properties was investigated by characterizing the films using scanning electron microscopy (SEM), x-ray reflectometry (XRR), nanoindentation and elastic recoil detection analysis (ERDA). Moreover the process characterization was done by recording the optical emission spectrum and current and voltage waveforms of the hybrid HiPIMS-DCMS discharge. The characterization of the films revealed that the hybrid HiPIMS-DCMS process is a powerful tool for controlling the amorphous carbon film properties such as density, deposition rate, hardness and hydrogen content.

There are many intensive researches for zinc compounds due to their wide band gaps and potential applications in visible and UV optoelectronic technologies. Zinc nitride is a n-type semiconductor material having a direct band gap, and is not widely studied. Previous papers reported that zinc nitride is a n-type semiconductor having low resistivity and high electron mobility. Its band gap varies from 1.23 eV to 3.2 eV depending on the process condition. In this work, we successfully fabricated zinc nitride p-n junction by heat treatment on zinc nitride films. The threshold voltage of p-n junction is about 1 V. The Zinc nitride films were prepared by reactive RF magnetron sputtering. The as-grown zinc nitride thin film is a n-type material. It is found that the film treated at 300¢J for 3 hours can be changed to a p-type material. The zinc nitride has a very low resistance (2.2¡Ñ10-2 £[-cm) and high carrier concentration (3.88¡Ñ1019 cm-3) after the heat treatment. The optical band gap of zinc nitride was determined as a direct band gap varying from 1.1 eV to 1.6 eV according to the temperature of heat treatment. The zinc nitride was successfully prepared with various electrical characteristics and band gaps by controlling the temperature of heat treatment.

Sputtering is a physical vapor deposition (PVD) process used to create thin films, i.e very thin layers of material. To form compounds, such as oxides and nitrides, it may be beneficial to add a reactive gas to the process which is known as reactive sputtering. This thesis focuses on the simulation of the reactive sputtering process and, more specifically, the effect of the process pressure. Two models have been developed. A Monte Carlo model simulates the distribution of sputtered material throughout the chamber. It is based on the binary collision model with initial conditions acquired from simulations in TRIM. The hard-sphere potential is used as interaction potential in the scattering calculations. The effect of the process pressure is studied for two different elements, sulfur and tungsten. It is found that the distribution of material is heavily influenced by the pressure. A high pressure gives a more diffusion-like distribution compared to a low pressure. As the pressure is increased the deposited material’s energy distribution is found to be shifted towards lower energies until it reaches the energy of thermalized atoms. The second model developed is an extended Berg model that incorporates the effect of redeposition of sputtered material on the target, implantation of reactive ions in the target and preferential sputtering. Using simulations the effect of these extensions is discussed. It is found that an increased pressure may eliminate the hysteresis region which has been observed experimentally. Finally an outline is presented on how the two models can be unified into a Berg-model that takes the non-uniform distribution of sputtered material into account.

Filmes finos de nitreto de silício com excesso de nitrogênio foram depositados sobre silício por sputtering reativo para obter estruturas emissoras de luz. As amostras foram modificadas por implantação iônica para verificar a influência dos dopantes arsênio (As) e boro (B) nos espectros de fotoluminescência (PL). As medidas de PL foram realizadas na faixa de temperatura entre 15-300 K e apresentaram uma emissão entre os comprimentos de onda 370-870 nm. Os dopantes introduziram uma emissão em 725 nm na banda de emissão, principalmente as dopadas com As. Foram realizadas medidas de microscopias para verificar a presença de nanoestruturas assim como a distribuição dos dopantes no material. As imagens de microscopias confirmaram a presença de nanocristais de nitreto de silício nas fases α, β e γ e identificaram a presença do dopante B nas fases cristalinas. O modelo de condução de Pool-Frenkel domina o transporte de portadores, indicando que a condução ocorre pelos níveis intrabandas, característica que definiu o modo que as recombinações radiativas ocorreram. As medidas de eletroluminescência (EL) apresentaram uma emissão centrada nos comprimentos de onda 760 e 880 nm (polarização negativa) e 1010 nm (polarização positiva) revelando diferenças significativas quando comparadas com as medidas de PL. Essa diferença esta associada à maneira como os elétrons populam os níveis intrabanda (excitação óptica para PL e elétrica para EL) que resulta em recombinações radiativas em diferentes comprimentos de ondas. A intensidade dos espectros de EL manifestou uma dependência quase linear com a densidade de corrente para ambas as polarizações. As medidas de EL em campos alternados exibiram um espectro de emissão composto pela soma das bandas obtidas separadamente em cada uma das polarizações. Medidas de EL em diferentes temperaturas (50-300 K) foram realizadas para investigar a influência da temperatura nos processos de recombinação radiativa. A intensidade exibiu uma redução com o aumento da temperatura, devido ao aumento do acoplamento elétron-fônon. / Silicon nitride with excess of nitrogen thin films were deposited on silicon substrate by reactive sputtering in order to obtain light emitting structures. Samples were modified by ion implantation of arsenic (As) and boron (B) to ascertain dopant leverage at photoluminescence (PL) spectra. PL measurements were performed at temperature ranging from 15 K up to 300 K and showed a band emission between wavelength 370 and 870 nm. An emission centered at 725 nm was observed in doped samples; especially in the presence of As. Microscope images showed crystalline structures of α-Si3N4, β-Si3N4 and γ-Si3N4 and confirmed boron dopant in nanocrystalline structures. Pool-Frenkel conduction model dominates electron transport in non-stoichiometric silicon nitride films due to intraband levels, phenomenon that has a huge contribution to electroluminescence (EL) emission. EL signals were composed by two peaks centered at 760 and 880 nm (negative bias – EL-N) and one peak at 1010 nm (positive bias – EL-P). Diffences between PL and EL spectra exhibit a clear dependence on the mode of excitation (photo and current source) on radiative recombination process. EL intensity had almost a linear increase with current density for both polarizations. EL measurements under AC voltage were composed by a superposition of the signals from EL-N and EL-P signals. Photo and electroluminescence measurements were collected at different temperatures (50 to 300 K) in order to investigate the temperature influence on the radiative recombination. The EL intensity was decreasing with temperature increasing, due to electron-phonon interactions.

Filmes finos de nitreto de silício com excesso de nitrogênio foram depositados sobre silício por sputtering reativo para obter estruturas emissoras de luz. As amostras foram modificadas por implantação iônica para verificar a influência dos dopantes arsênio (As) e boro (B) nos espectros de fotoluminescência (PL). As medidas de PL foram realizadas na faixa de temperatura entre 15-300 K e apresentaram uma emissão entre os comprimentos de onda 370-870 nm. Os dopantes introduziram uma emissão em 725 nm na banda de emissão, principalmente as dopadas com As. Foram realizadas medidas de microscopias para verificar a presença de nanoestruturas assim como a distribuição dos dopantes no material. As imagens de microscopias confirmaram a presença de nanocristais de nitreto de silício nas fases α, β e γ e identificaram a presença do dopante B nas fases cristalinas. O modelo de condução de Pool-Frenkel domina o transporte de portadores, indicando que a condução ocorre pelos níveis intrabandas, característica que definiu o modo que as recombinações radiativas ocorreram. As medidas de eletroluminescência (EL) apresentaram uma emissão centrada nos comprimentos de onda 760 e 880 nm (polarização negativa) e 1010 nm (polarização positiva) revelando diferenças significativas quando comparadas com as medidas de PL. Essa diferença esta associada à maneira como os elétrons populam os níveis intrabanda (excitação óptica para PL e elétrica para EL) que resulta em recombinações radiativas em diferentes comprimentos de ondas. A intensidade dos espectros de EL manifestou uma dependência quase linear com a densidade de corrente para ambas as polarizações. As medidas de EL em campos alternados exibiram um espectro de emissão composto pela soma das bandas obtidas separadamente em cada uma das polarizações. Medidas de EL em diferentes temperaturas (50-300 K) foram realizadas para investigar a influência da temperatura nos processos de recombinação radiativa. A intensidade exibiu uma redução com o aumento da temperatura, devido ao aumento do acoplamento elétron-fônon. / Silicon nitride with excess of nitrogen thin films were deposited on silicon substrate by reactive sputtering in order to obtain light emitting structures. Samples were modified by ion implantation of arsenic (As) and boron (B) to ascertain dopant leverage at photoluminescence (PL) spectra. PL measurements were performed at temperature ranging from 15 K up to 300 K and showed a band emission between wavelength 370 and 870 nm. An emission centered at 725 nm was observed in doped samples; especially in the presence of As. Microscope images showed crystalline structures of α-Si3N4, β-Si3N4 and γ-Si3N4 and confirmed boron dopant in nanocrystalline structures. Pool-Frenkel conduction model dominates electron transport in non-stoichiometric silicon nitride films due to intraband levels, phenomenon that has a huge contribution to electroluminescence (EL) emission. EL signals were composed by two peaks centered at 760 and 880 nm (negative bias – EL-N) and one peak at 1010 nm (positive bias – EL-P). Diffences between PL and EL spectra exhibit a clear dependence on the mode of excitation (photo and current source) on radiative recombination process. EL intensity had almost a linear increase with current density for both polarizations. EL measurements under AC voltage were composed by a superposition of the signals from EL-N and EL-P signals. Photo and electroluminescence measurements were collected at different temperatures (50 to 300 K) in order to investigate the temperature influence on the radiative recombination. The EL intensity was decreasing with temperature increasing, due to electron-phonon interactions.

With the rapid increase in miniaturization of mechanical components, the need for a hard, protective coatings is of great importance. In this study we investigate some of the mechanical, chemical and physical properties of the SiCN thin films. Thin films of amorphous silicon carbide nitride (a-SiCxNy) were deposited in a RF magnetron sputtering system using a powder pressed SiC target. Films with various compositions were deposited on to silicon substrate by changing the N2/Ar gas ratios during sputtering. Nano-indentation studies were performed to investigate the mechanical properties such as hardness and reduced modulus of the SiCN films. Surface morphology of the films was characterized by using atomic force microscopy (AFM). X-ray photoelectron spectroscopy (XPS) data indicated that the chemical status is highly sensitive to the nitrogen ratios during sputtering. Further, the films were annealed in dry oxygen ambient in the temperature range of 400 – 900°C and characterized using XPS to investigate the chemical composition and oxidation kinetics at each annealing temperature. The surface roughness of these films was studied as a function of annealing temperature and film composition with the help of a "Veeco" optical profilometer. Nano-indentation studies indicated that the hardness and the reduced modulus of the film are sensitive to the N2/Ar ratio of gas flow during sputtering. AFM studies revealed that the films become smoother as the N2/Ar ratio is increased. XPS data indicated the existence of C-N phases in the as-deposited films. The study of oxidation kinetics of RF sputter deposited SiCN thin films, using XPS, suggest that N2 co-sputtering helps to suppress the formation of a surface oxide, by allowing un-bonded Si to bond with N and C inside the vacuum chamber as opposed to bonding with O in atmosphere.