Study on Heat and Mass Transport in Liquid during Faceted Cellular Array Growth

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In materials whose entropy change due to fusion are large, such as semiconductor, oxide superconductor and other crystalline materials, faceted cellular morphology is often observed on the advancing solid/liquid interface. The mechanism to maintain this faceted morphology at steady-state growth had been accepted by many researchers to be solute pile-up and subsequent undercooling at the bottom of the cellular interface. Higashino, Inatomi and Kuribayashi (HIK), however, reported the appearance of a recalesced region ahead of the faceted interface in transparent organic compounds, using an optical interferometer. In the present study, precise measurement of the temperature distribution ahead of the advancing interface was carried out by means of an interferometric visualization technique as well as a conventional temperature measurement technique using microthermocouples. The result is that the influence of latent heat on the temperature distribution ahead of the interface was correlated qualitatively with a nondimensional parameter defined by the release rate and the diffusion flux of latent heat. In addition, morphological instabilities of the faceted interface were attributed to the change in the temperature distribution.