XRD Investigations of Co Films Deposited by CVD 20 th International Conference for Students and Young Scientists «Modern Technique and Technologies MTT 2014» April 2014, Tomsk, Russia Rustam Hairullin National Research Tomsk Polytechnic University

2 Outline 1.Why Co films and why CVD? 2.Research materials and methods 3.Results 4.Conclusion

3 Hard disk drive Magnetic sensor for checking the availability of protective magnetic marks on banknotes Background Why Co films and why CVD?

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, 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 4 gas-carrier 4 gas-reagent pumping Why Co films and why CVD? Background

5 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: 1.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. 2.To establish links between structure and magnetic characteristics of Co films. Aim and Problems

Research Materials and Deposition Conditions 6 First setSecond set Ts,0СTs,0СT vap, 0 СTs,0СTs,0С Deposition conditions of Co films, where Т s – substrate temperature, Т vap – vaporization temperature Substrate: Si Gas-carrier: Ar Gas-reagent: H 2 The operating pressure: 1 atm Duration of deposition: 4 h

Research Methods 7 Phase composition, sizes of CSR and values of microstresses X-ray diffraction analysis Chemical composition Energy-dispersive X-ray spectroscopy Magnetic characteristics Vibromagnetometer

8 XRD patterns of the Co films deposited at different substrate temperatures and at vaporization temperature T vap =120 (a) and 130 °С (b) а b Results of XRD Investigations β-Co (111), 2Ө = 44,3 ○ α-Co (002), 2Ө = 44,6 ○.

9 Т vap, 0 СТ s, 0 СChemical compositionCSR, nm , GPa First set Co 91.4%, C 8.3 %, O 0.3% 171, Co 89.9%, C 9.5%, O 0.6% 151, Co 84.1%, C 11.6%, O 4.3% 191, Co 80.0%, C 18.9%, O 1.1% 131, Co 44.2%, C 55.7%, O 0.1% 110,8 Second set Co 84.8%, C 14.2%, O 0.1%, N 0.9 %350, Co 86.5%, C 12. 6%, O 0.2%, N 0.7 %260, Co 92.3%,C 7. 2%, O 0.5%330, Co 93.5%, C 6.0%, O 0.5%260, Co 90.9%, C 8.8%, O 0.3%200,3 Chemical composition, CSR size and microstresses  of Co films deposited at different vaporization T vap and substrate T s temperatures Results of XRD Investigations

10 Hysteresis loops of Co films deposited at T s = 330 °С and T vap = 120 (а) and С (b), as well as at T s = 320 °С and T vap = С (c) аb c The Effect of Substrate Temperature and Vaporization Temperature on Magnetic Properties of Co Films

11 Conclusion The results of the performed investigations show: substrate temperature from 310 up to 420  С cobalt content, sizes of the coherent scattering region and values of microstresses of Co films vaporization temperature from 120 up to 130  С 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

12 Thank you for your attention!