Focused Ion Beam Imaging of Defects in Multicrystalline Si for Photovoltaic Application

Y. Miyamuraa, T. Sekiguchia, b, J. Chena, J.Y. Lia, c, K. Watanabea, b, K. Kumagaia, d and A. Ogurac aMANA Nanoelectronic Materials Unit, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan bGraduate School of Pure and Applied Sciences, University of Tsukuba, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan cSchool of Science and Technology, Meiji University, Kawasaki 214-8571, Japan dNational Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan

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We demonstrate the imaging of the extended defects in Si materials using a focused ion beam instrument. Since Ga-ion beam has small penetration depth and high channeling character compared with electron beam, the secondary electron signal of focused ion beam is more sensitive to the surface morphology and crystallinity. We have tried to use this secondary electron imaging of focused ion beam for observation of various extended defects in Si materials for photovoltaic and semiconductor devices. As for the texture of multicrystalline Si, some grains are imaged darker than the others. It suggests that the crystal orientation gives different channeling effect on the primary Ga-ion beam, resulting in the different secondary electron yield. The grain boundaries and lineage in multicrystalline Si are shown as bright lines and patterns in the image. Although it may reflect the surface morphologies, these contrasts may be attributed to the channeling contrast due to lattice displacement or distortion. The contrast mechanism of FIB imaging is discussed.

DOI: 10.12693/APhysPolA.125.991 PACS numbers: 61.05.-a, 61.85.+p, 61.72.Ff