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20 th International Conference for Students and Young Scientists «Modern Technique and Technologies MTT 2014». XRD Investigations of Co Films Deposited by CVD. Rustam Hairullin. National Research Tomsk Polytechnic University. 14-18 April 201 4, Tomsk, Russia. Outline.
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20th International Conference for Students and Young Scientists «Modern Technique and Technologies MTT2014» XRD Investigations of Co Films Deposited by CVD RustamHairullin National Research Tomsk Polytechnic University 14-18 April 2014,Tomsk, Russia
Outline Why Co films and why CVD? Research materials and methods Results Conclusion
Why Co films and why CVD? Background Magnetic sensor for checking the availability of protective magnetic marks on banknotes Hard disk drive
Why Co films and why CVD? Background pumping gas-reagent 4 gas-carrier Scheme autonomous device with dual-zone evaporator for deposition layers on flat samples : 1 - stainless steel reactor, 2 - quartz boat containing the starting compound I, 3 - quartz boat containing the starting compound II, 4 – container, 5 - warmed conduit, 6 - shaper of gas flow, 7-9 - resistive heaters, 10 - a substrate, 11 - a substrate holder, 12 - substrate heater, 13 – solenoid, 14 - movable electrical contacts, 15 – unit of the substrate rotation, 16 - the gateway device, 17 - chamber for 6 samples, 18 - the tube for supplying the reactant gas
Aim and Problems The aim of this research: to investigate the effect of deposition conditions on the structure of Co thin films deposited by Chemical Vapor Deposition (CVD). Problems: To reveal the effect of substrate and vaporization temperatures on phase and chemical composition, sizes of coherent scattering region (CSR) and value of microstresses of Co thin films. To establish links between structure and magnetic characteristics of Co films.
Research Materials and Deposition Conditions Deposition conditions of Co films, where Тs– substrate temperature, Тvap– vaporization temperature Substrate: Si Gas-carrier: Ar Gas-reagent: H2 The operating pressure: 1 atm Duration of deposition: 4 h
Research Methods Phase composition, sizes of CSR and values of microstresses X-ray diffraction analysis Energy-dispersive X-ray spectroscopy Chemical composition Vibromagnetometer Magnetic characteristics
Results of XRD Investigations а β-Co (111),2Ө = 44,3○ α-Co (002), 2Ө = 44,6○. b XRD patterns of the Co films deposited at different substrate temperatures and at vaporization temperature Tvap =120 (a) and 130 °С (b)
Results of XRD Investigations Chemical composition, CSRsizeand microstresses of Co films deposited at different vaporization Tvap and substrate Ts temperatures
The Effect of Substrate Temperature and Vaporization Temperature on Magnetic Properties of Co Films а b c Hysteresis loops of Co films deposited at Ts= 330 °С andTvap= 120 (а) and130 0С (b), as well as atTs= 320 °С andTvap= 130 0С (c)
Conclusion • The results of the performed investigations show: • substrate temperature from 310 up to 420С • cobalt content, sizes of the coherent scattering region and values of microstresses of Co films • vaporization temperature from 120 up to 130С • values of microstresses, the CSR, • degree of substrate temperature’s effect on values of microstresses and chemical composition • cobalt content and CSR residual and saturation magnetization • degree of texture coercive force 1 2 3 4