Segregation during the seeding process in the Czochralski growth of GeSi alloys

The hetero-seeding and segregation processes in the growth of bulk crystals of GeSi alloys by the Czochralski method were investigated. Full single crystals were obtained from a melt of low Si content GeSi or pure Ge by using a Si seed while crystals grown by using a Ge seed became polycrystalline in the early stage of growth. The abrupt and gradual transition of the compositions from the Si and Ge seeds, respectively, to the grown alloy crystals were detected by means of energy dispersive X-ray spectroscopy. Segregation during the growth initiation process is discussed in terms of the unstable solidification of the growth using a Ge seed. (C) 1998 Elsevier Science B.V. All rights reserved.