XRD Investigations of Co Films Deposited by CVD

20th International Conference for Students and Young Scientists

«Modern Technique and Technologies MTT 2014»

14-18 April 2014, Tomsk, Russia

Rustam Hairullin National Research Tomsk Polytechnic University

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Outline

1. Why Co films and why CVD?

2. Research materials and methods

3. Results

4. Conclusion

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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, 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

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gas-carrier

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gas-reagent

pumping

Why Co films and why CVD?

Background

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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

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First set Second setTs,

0С Tvap,0С Ts,

0С Tvap,0С

310 120 300 130

330 120 310 130

350 120 320 130

370 120 330 130

420 120 340 130

Deposition conditions of Co films, where Тs – substrate temperature, Тvap – vaporization temperature

Substrate: SiGas-carrier: ArGas-reagent: H2

The operating pressure: 1 atmDuration of deposition: 4 h

Research Methods

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Phase composition, sizes of CSR and values of microstresses

X-ray diffraction analysis

Chemical composition Energy-dispersive X-ray spectroscopy

Magnetic characteristics Vibromagnetometer

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XRD patterns of the Co films deposited at different substrate temperatures and at vaporization temperature Tvap =120 (a) and 130 °С (b)

а b

Results of XRD Investigations

β-Co (111), 2Ө = 44,3○

α-Co (002), 2Ө = 44,6○.

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Тvap, 0С Тs,

0С Chemical composition CSR, nm

, GPa

First set120 310 Co 91.4%, C 8.3 %, O 0.3% 17 1,7

120 330 Co 89.9%, C 9.5%, O 0.6% 15 1,4

120 350 Co 84.1%, C 11.6%, O 4.3% 19 1,2

120 370 Co 80.0%, C 18.9%, O 1.1% 13 1,4

120 420 Co 44.2%, C 55.7%, O 0.1% 11 0,8

Second set130 300 Co 84.8%, C 14.2%, O 0.1%, N 0.9 % 35 0,4

130 310 Co 86.5%, C 12. 6%, O 0.2%, N 0.7 % 26 0,5

130 320 Co 92.3%,C 7. 2%, O 0.5% 33 0,2

130 330 Co 93.5%, C 6.0%, O 0.5% 26 0,4

130 340 Co 90.9%, C 8.8%, O 0.3% 20 0,3

Chemical composition, CSR size and microstresses of Co films deposited at different vaporization Tvap and substrate Ts temperatures

Results of XRD Investigations

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Hysteresis loops of Co films deposited at Ts = 330 °С and Tvap = 120 (а) and 130 0С (b), as well as at Ts = 320 °С and Tvap = 130 0С (c)

а b

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The Effect of Substrate Temperature and Vaporization Temperature on Magnetic Properties of Co Films

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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

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Thank you for your attention!