Theoretical Analysis and Experimental Verification of Triangular Fracture Defects of MgO Single Crystal Substrate in Lapping or Polishing Process

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Abstract:

MgO single crystal is mainly used as substrate for high temperature superconductor film. Surface quality of MgO substrate has significant effect on the function of high temperature superconductor film. MgO single crystal is a typical hard and brittle material, and is easily cleaved along the {100} face, so some defects are always generated on the substrate surface while lapping and polishing, which badly affects the surface quality of the substrate. In this paper, a kind of typical defect, the triangular fracture defect which is on the substrate surface after lapping and polishing, is analyzed in detail. According to the structure characteristics of the MgO single crystal, and based on the dislocation reaction theory, a formation mechanism of the triangular fracture defect in lapping and polishing processes is explored. Through the single grain scratch test in different directions on the polished surface of MgO{100} single crystal substrates, the formation mechanism of triangular fracture defect in lapping and polishing processes is verified. And during the scratch test, the plastic flow of the MgO single crystal material beside the scratch was observed.

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Periodical:

Key Engineering Materials (Volumes 364-366)

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739-744

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December 2007

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© 2008 Trans Tech Publications Ltd. All Rights Reserved

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[1] Jeong-Du Kim, Eun-Sang Lee. Surface characteristics on the ductile mode grinding of MgO,Journal of Machine Tools Manufacturing, 1998(38): 97~111.

Google Scholar

[2] Mitchell E E, Gnanarajan S, Green K L, Foley C P. The effect of MgO substrate roughness on YBa2Cu3O7-δthin film properties. Thin Solid Film, 2003, 437: 101~107.

DOI: 10.1016/s0040-6090(03)00609-6

Google Scholar

[3] M. Schieber, Y. Ariel. Dependence of superconducting properties of thin films of YBa2Cu3O7-δ on structural parameters of the films and substrates. Appl. Phys. Lett. 1992(61): 970-972.

DOI: 10.1063/1.107744

Google Scholar

[4] Sangsub Kim, Sunggi Baik. Effects of surface structures of MgO(100) single crystal substrates on ferroelectric PbTiO3 thin films grown by radio frequency sputtering, Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 1995(13): 95-100.

DOI: 10.1116/1.579392

Google Scholar

[5] N. Dammak et al. Study of charging phenomena in MgO single crystal: effect of polishing, annealing temperature and crystallographic orientation, Journal of the European Ceramic Society, 2002 (22): 1149-1154.

DOI: 10.1016/s0955-2219(01)00427-7

Google Scholar

[6] T. Harada, H. Ohkoshi. Influence of MgO(100) substrate surfaces on epitaxial growth of Ti films, Journal of Crystal Growth, 1997 (173): 109-116.

DOI: 10.1016/s0022-0248(96)00787-7

Google Scholar

[7] A. S Keh. J.C.M. Li and Y.T. Chou. Cracks due to the piling-up of dislocations on two intersecting slip planes in MgO crystals. Acta metal. 1959(7): 694~696.

DOI: 10.1016/0001-6160(59)90156-7

Google Scholar

[8] M. M Chaudhri, Yuji Enomoto. In situ observation of indentation damage in single crystals of MgO. Wear. 1999(233-235): 717~726.

DOI: 10.1016/s0043-1648(99)00178-7

Google Scholar

[9] N. Khasgiwale, H.M. Chan. Indentation induced crack nucleation and propagation in single crystal MgO. Acta metall. mater. 1995(43): 207~215.

DOI: 10.1016/0956-7151(95)90276-7

Google Scholar