Regensburg 2004 – scientific programme
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HL: Halbleiterphysik
HL 44: Poster II
HL 44.68: Poster
Thursday, March 11, 2004, 16:30–19:00, Poster A
Undercooling and Solidification of Liquid Silicon — •C. Panofen1, R.P. Liu2, G. Lohöfer1 und D.H. Herlach1 — 1Institut für Raumsimulation, DLR, Köln — 2Yanshan University, Qinhuangdao, P.R. China
Containerless processing by electromagnetic and electrostatic levitation techniques was applied to undercool and solidify pure Si melts in a high purity environment. Without surrounding crucible walls we achieved large undercoolings of up to 330K below the melting point due to the reduction of heterogeneous nucleation sites. A pyrometric sensor measured the sample temperature contactlessly. We stimulated crystallization by triggering with a silicon wafer at the desired undercooling. The velocity of the solidification front as a function of undercooling was directly determined by photo sensors and a high speed camera. We analyzed the growth behavior within current theories of crystal growth in undercooled melts. Special emphasis was placed to a microstructure transition from faceted to dendritic growth. The results of the growth measurements were correlated to microstructure formation upon undercooling prior to solidification.
This work was supported by DFG under contract No. HE1601/16-1 and the Sino-German Science Center Beijing.