People always think of the RADAR with military then talking about it and it is reasonable. The development of RADAR is depended on military requirement and be emphasized, noticed in the war. Come with the technology development of RADAR. It was effect the human life and economic activity more and more. In fact, most of the technologies for RADAR system are used by military and civilian. However, the characteristic of RADAR except circuit design but selection micro-tube also. There are many main points the power output, pulse width, duty cycle, update rate etc. are different key points when the RADAR system were designed. This thesis included three main parts. First, the characteristics and the functions of magnetron, klystron and traveling wave tube were compared and analyzed by RADAR system designed. This specification can be use for RADAR maintenance. Secondarily, the purpose is to research the VMX1389 type magnetron and SFD354H type magnetron and compare automatic frequency control, design and manufacture adapter for VMX1389 tube. The third, according to test tension which change the cavity and frequency of tube between two coaxial magnetron and find out the servo motor then analyze it. We set up a testing system to test the coaxial magnetron also. Using hand adjusting the magnetron tube to match local oscillator frequency and to get a stable feedback signal then control output frequency is the final thesis result. All the purpose of this thesis is to modify the magnetron and to resolve the CSS RADAR system without magnetron.

Recently material physics group at Science Institute of University of Iceland has been using reactive sputtering to grow thin films used in various research projects at the institute. These films have been grown using dc sputtering which has been proven a very successful method. High power impulse magnetron sputtering or HiPIMS is an new pulsed power sputtering method where shorter but high power pulses are used to sputter over lower steady power. The project resulted in a functional system capable of growing thin films using HiPIMS. Thin films grown with high power pulses have a higher film density and other more preferable properties compared to films grown using direct current magnetron sputtering.

Precise control techniques are of fundamental importance in the accurate deposition of optical, mechanical, electrical and magnetic thin films. The objective of this work was twofold: to devise and evaluate novel control systems for reactive sputtering primarily oxide films, and investigate the effects of these processes on resultant film properties.

It is well known that ion bombardment of growing films can strongly influence their microstructure and consequently their physical properties. The available technology for ion assisted deposition, particularly where separate sources are used for the deposition flux and the ion flux, is difficult to implement in many production situations. The planar magnetron provides a controllable ion flux while retaining the many other desirable features of simplicity, high deposition rate, geometric versatility and tolerance of reactive gases. This assists in the implementation of ion beam assisted deposition in both research and production.

Magnetron is a crossed-field vacuum tube and has found applications in many fields where high power microwave is required, such as meteorological radar, marine navigation, particle accelerator and domestic and industrial heating. When the operating frequencies are in millimetre-wave/THz band, conventional magnetrons show an inherent limitation due to complex small structure, short life time and intense magnetic field. Recently, the Spatial Harmonic Magnetron (SHM) has been proved to be an effective alternative to conventional magnetron for millimetre-wave/THz applications with the advantages of simple anode structure, sufficient life time, low voltage and magnetic field. However, the physics of the operation of SHM have not been adequately understood. In this thesis, considerable insight into the SHM operation has been obtained based on the 3-D particle simulation and experiment. The investigation of a 16-vane SHM operating in the π/2-1 mode at 35GHz reveals that the cathode current mainly depends on the electron secondary emission from the cold cathode rather than the injection current from the side cathode. The smaller secondary emission coefficient causes noisy output spectrum and low output power. When the secondary emission coefficient reduces below a threshold value, the oscillation cannot start. The transient behaviour shows that the neighbouring modes compete with the working mode. The particle-in-cell (PIC) simulation of a π/2 SHM demonstrates that the oscillation could jump from the working mode to its neighbouring mode with a slight change of the anode voltage. The simulated performance on a compact 95 GHz SHM is in a good agreement with the measured one. A number of engineering issues, such as the pulse duration, the anode temperature and vacuum break down have been considered for the SHM to deliver more than 5kW peak power with 200ns pulse in 0.05% duty cycle. The quality of output signal pulses assessed in the experiment indicates that this SHM can be effectively used for the development of low cost W-band cloud radar. There are a number of technical challenges in designing and fabricating THz-band SHMs with good performance, such as fabrication of a large number of cavities and the cold cathode. The modelling of a 40-vane 209 GHz SHM operating on the π/2-1 mode and the measurement on fabricated anode cavity indicates that the fabrication tolerance should be taken into account in the design of a high frequency SHM. Based on the analysis on a 44-cavity anode, the π/2-3 mode is chosen to improve the mode stability. The PIC simulation indicates that such magnetrons can deliver at least 0.6 kW peak power at a frequency above 300GHz.

Made available in DSpace on 2014-06-12T18:05:51Z (GMT). No. of bitstreams: 2 arquivo7695_1.pdf: 2537717 bytes, checksum: 60ca15ac8000b97ca710ead44bed4782 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 1996 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Neste trabalho é estudado a deposição de filmes finos metálicos e refratários por magnetron sputtering utilizando-se tanto de uma fonte de como rf. Os pontos ótimos de trabalho foram determinados em função da pressão na câmara de deposição e da potência das fontes para os seguintes materiais: Nb, Ti, Mo, W e Si, obtendo assim um treinamento na utilização da máquina de deposição ao mesmo tempo que preparando-a para futuros usuários. Especial atenção é dada à deposição e caracterização de filmes finos de Nb com espessura entre 300 Å e 10000 Å. As características supercondutoras destes filmes são analisadas através de medidas de susceptibilidade ac, magnetização dc e da razão de resistência. O diagrama de fase campo magnético temperatura (H-T), obtido de seqüências de esfriamento a campo nulo (ZFC) e em campo (FC), revela uma forte dependência da linha de irreversibilidade com a espessura do filme. Em filmes mais finos a região de irreversibilidade diminui. Este efeito é atribuído a danos superficiais causados por tensões ou por defeitos

β-W is an A15 structured phase commonly found in tungsten thin films together with the bcc structured W, and it has been found that β-W has the strongest spin Hall effect among all metal thin films. Therefore, it is promising for application in spintronics as the source of spin-polarized current that can be easily manipulated by electric field. However, the deposition conditions and the formation mechanism of β-W in thin films are not fully understood. The existing deposition conditions for β-W make use of low deposition rate, high inert gas pressure, substrate bias, or oxygen impurity to stabilize the β-W over α-W, and these parameters are unfavorable for producing β-W films with high quality at reasonable yield. In order to optimize the deposition process and gain insight into the formation mechanism of β-W, a novel technique using nitrogen impurity in the pressure range of 10-5 to 10-6 torr in the deposition chamber is introduced. This techniques allows the deposition of pure β-W thin films with only incorporation of 0.4 at% nitrogen and 3.2 at% oxygen, and β-W films as thick as 1μm have been obtained. The dependence of the volume fraction of β-W on the deposition parameters, including nitrogen pressure, substrate temperature, and deposition rate, has been investigated. The relationship can be modeled by the Langmuir-Freundlich isotherm, which indicates that the formation of β-W requires the adsorption of strongly interacting nitrogen molecules on the substrate. The dependence of β-W formation on the choice of underlayer materials has also been investigated. The β-W phase can only be obtained on the underlayer materials containing non-metallic elements. The dependence is explained by the existence of strong covalent bonds in β-W compared with that in α-W. The nickel and permalloy underlayers are the only exception to the above rule, and β-W has been successfully deposited on permalloy underlayer using very low deposition rate for spin-diffusion length measurement of β-W. The permalloy thin films usually take the (111) texture, since its (111) planes have the lowest surface energy. However, permalloy thin films deposited on β-W underlayer can achieve (002) texture using amorphous glass substrates. Therefore, the permalloy/β-W bilayer system can work as a seed layer for the formation of (002) textured films with fcc or bcc structure. The mechanism of the (002) texture formation cannot be explained by the existing models. The β-W to α-W phase transition was characterized by differential scanning calorimetry. The enthalpy of transformation is measured to be 8.3±0.4 kJ/mol, consistent with the value calculated using density functional theory. The activation energy for the β-W to α-W phase transformation kinetics is 2.2 eV, which is extremely low compared with that of lattice and grain boundary diffusion in tungsten. The low activation energy might be attributed to a diffusionless shuffle transformation process.

Silicon and silicon nitride thin films were growth on Si and glass substrates at room temperature by ratio-frequency (r-f) magnetron sputtering. The electrical characteristics of the silicon nitride films were characterized using I-V and C-V measurement under different growth condition, including r-f power, nitrogen partial pressure, and hydrogen partial pressure. Minimum current leakages for MIS structure as low as 2¡Ñ10 A/cm were obtained at 1 MV/cm electrical field with hysteresis voltage about 2V. The root-mean square surface roughness of the silicon nitride film is less then 1nm. In addition, silicon nitride capacitors with indium-tin-oxide as electrodes were fabricated. Silicon thin films prepared by R.F. magnetron sputtering at room temperature are amorphous. The measurements on the variation of the photo-conductivity were used to characterize the characteristics of the Si film.

No description available.

O PVD (Physical Vapor Deposition- Deposição física na fase de vapor) é um meio utilizado para a produção de recobrimentos e empregado em grande escala industrial. É um processo de deposição atômica no qual o material é vaporizado de alvo sólido por sputtering e posteriormente condensado sobre a peça a ser revestida na forma de filme. O processo ocorre em uma câmara de vácuo, na presença de plasma, e por diferença de potencial os íons, na forma pura ou combinados com átomos de hidrogênio ou carbono, são movidos para a superfície do substrato. Uma técnica relativamente nova de sputtering é o HiPIMS (High Power Impulse Magnetron Sputtering) que utiliza impulsos de energia extremamente altas com densidade de potência possibilitando filmes com melhores performances e mais densos. No presente trabalho filmes de nitreto de cromo (CrN) foram depositados por duas técnicas de magnetron sputtering, HiPIMS e DCMS (Direct Current Magnetron Sputtering), variando frequência de pulso em 400 Hz, 450 Hz e 500 Hz para o HiPIMS e a tensão de polarização em 0 V, -20 V, -40V, -60V, - 100 V e -140 V para os dois processos. Foram obtidos filmes com maior dureza, menor rugosidade para HiPIMS, no entanto DCMS apresentou maior taxa de deposição. O aumento da frequência nos filmes HiPIMS, assim como o aumento da tensão de polarização negativa possibilitaram filmes com morfologia mais densa e homogênea. Este fato também foi observado com o aumento do valor de bias nos filmes depositados por DCMS. Os valores de dureza obtidos (17 ± 2 para DCMS e 26 ± 1 para HiPIMS) são superiores aos reportados na literatura e podem estar relacionados ao efeito de \"multicamadas\" obtido pela oscilação do substrato. / PVD (Physical Vapor Deposition) is a process used for coatings deposition and it is used on a large industrial scale. It is an atomic deposition process in which the material is vaporized from solid target by sputtering and then condensed onto the part to be coated in film form. The process occurs in a vacuum chamber in the presence of plasma, and by potential difference the ions in pure form or combined with hydrogen or carbon atoms are moved to the surface of the substrate. A relatively new sputtering technique is the HiPIMS (High Power Impulse Magnetron Sputtering) which uses extremely high energy pulses with power density to enable higher performance and denser films. In the present work, chromium nitride (CrN) films were deposited by two magnetron sputtering techniques, HiPIMS and DCMS (Direct Current Magnetron Sputtering), varying the pulse frequency at 400 Hz, 450 Hz and 500 Hz for the HiPIMS and the bias at 0 V, -20 V, -40 V, -60 V, -100 V and -140 V for both processes. It was obtained films with high hardness, less roughness for HiPIMS, however DCMS presented a higher rate of deposition. The increase of the frequency in the HiPIMS films, as well as the increase of the negative polarization voltage, allowed films with denser and homogeneous morphology. This fact was also observed with the increase of the value in the films deposited by DCMS. The hardness values obtained (17 ± 2 for DCMS and 26 ± 1 for HiPIMS) were higher than those reported in the literature and may be related to the \"multilayer\" effect obtained by substrate oscillation.