Thermal Diffusivities and Conductivities of Molten Germanium and Silicon

Nishi, Tsuyoshi; Shibata, Hiroyuki; Ohta, Hiromichi

doi:10.2320/matertrans.44.2369

Cited by 38 publications

(19 citation statements)

References 14 publications

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“…The temperature differences between the end walls at the moment when solidification started were measured to be between 80 and 120 K, so ΔT = 100 K on average. Taking a melt depth of 2mm as characteristic length z, and with ∂γ/∂T= -0.6·10 −3 N/m·K for a 3% Si concentration [24], η = 0.74·10 −3 Pa·s (Ge value from [26]), and κ = 2.37·10 −5 m 2 /s (Ge value from [27]), one obtains Ma T = 6840.…”

Section: Resultsmentioning

confidence: 99%

Solutocapillary convection in germanium‐silicon melts

Cröll¹,

Mitric

Aniol

et al. 2009

Cryst. Res. Technol.

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Surface tension gradients in free crystal growth melts give rise to convective flow. If these gradients are due to thermal gradients, the well known thermocapillary (Marangoni) convection ensues. Concentration gradients due to segregation at the interface during growth can lead to additional solutocapillary convection. A system with large solutocapillary convection is Ge-Si due to the pronounced segregation and the strong difference in surface tension; solutal buoyancy convection is also present due to the large density difference between Ge and Si. Solutocapillary convection will oppose thermocapillary convection in the Ge-Si system since Si, having the higher surface tension, is preferentially incorporated into the crystal. A set of experiments directly proving and partially quantifying the effect has been conducted under microgravity during a parabolic flight campaign by recrystallizing Ge-Si mixtures of different compositions, between 3% and 9% Si, in a crucible with tracers to visualize the movement. Solutocapillary flow with initial flow rates in excess of 5.5 cm/s at the onset of crystallization was measured. A slight dependence of the flow velocity on the initial Si content has been found. Experiments on the ground showed the same effect but with overall smaller speeds; this difference can be explained by the additional action of solutal buoyancy convection. Dedicated to Prof. Wolfgang Neumann on the occasion of his 65th birthday

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Section: Resultsmentioning

confidence: 99%

Solutocapillary convection in germanium‐silicon melts

Cröll¹,

Mitric

Aniol

et al. 2009

Cryst. Res. Technol.

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“…The existence of the surface-tension-driven flow, i.e. the Marangoni flow, of molten (53) (24,54,55) silicon was confirmed through crystal growth experiment under microgravity conditions [57]. The driving force for Marangoni flow is a shear force due to the surface-tension difference at the melt surface.…”

Section: Surface Tensionmentioning

confidence: 95%

“…15 Thermal conductivity, directly measured in various magnetic fields between 0.5 and 4 T[35] and estimated from thermal diffusivity and electrical conductivity[5,7,8,24,[52][53][54][55][56].…”

mentioning

confidence: 99%

Thermophysical Properties of Molten Silicon

Hibiya

Fukuyama

Tsukada

et al. 2008

Crystal Growth Technology

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IntroductionModern society features information processing on a large scale and is supported by information technologies, which require high-speed data processing and high-speed data transmission. From the viewpoint of materials science and engineering, this is supported by high-quality semiconductor crystals, produced from high-temperature melt processes, such as the Czochralski, the floating zone, Bridgman processes, and so on. In order to understand and control these high-temperature processes, computer modeling is one of the superior tools available. This shows us the physics of these processes and how to improve processes and products, as shown in Fig. 4.1 [1]. This has been made possible thanks to the year-by-year improvements in computer performance, and even turbulence flow can now be handled. In modeling equations for continuity, momentum, energy and the Maxwell equation are solved simultaneously. In order to calculate temperature, flow and pressure fields of a high-temperature process, the thermophysical properties of the molten state in particular are indispensable. A survey was carried out on the required thermophysical properties for silicon crystal growth processes and on thermophysical properties actually employed in modeling in Japan: see Fig. 4.2 and Table 4.1 [2][3][4]. Table 4.1 shows thermophysical properties employed in 44 papers. The scatter of the data is rather large; particularly for the temperature coefficient of surface tension, the difference is one order of magnitude. Historically, Glazov et al. [5] reviewed thermophysical properties of molten semiconductors not only for molten silicon but also for other compound molten semiconductors. However, modern society requires the development of new measurement techniques and improvements in the accuracy and precision of data. Iida and Guthrie [6] overviewed thermophysical properties of molten metals and methods for measurements; this is a good textbook for thermophysical property measurement of high-temperature melts. Figure 4.2 shows that thermal conductivity, specific heat capacity and surface tension are urgently required. Although thermal conductivity is required to calculate heat balance at the solid/liquid interface during crystal growth and is important to Crystal Growth Technology. Edited by Hans J. Scheel and Peter Capper

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“…3). The measurements of Nishi et al 31 and Takasuka et al 33 have been performed in laser-flash instruments, while the measurements of Yamasue et al 32 have been performed in a transient hot-wire instrument. Measurements from the first two investigators have successfully been employed in developing reference correlations of liquid metals in our previous publication 7 whereas in the same paper the measurements of Yamasue et al 9 were considered secondary data since they were much lower than all other measurements.…”

Section: Data Compilationmentioning

confidence: 99%

“…We should note here that from the eight investigators in Table 3, five employed instruments that measure the thermal diffusivity: Nishi et al 31 and Filippov 24 gave also thermal conductivity values, but to convert the values of Takasuka et al , 33 Taylor et al 34 and Crouch et al , 35 we employed literature values for the heat capacity 33 and the density. 45 …”

Section: Data Compilationmentioning

confidence: 99%

Reference Correlations for the Thermal Conductivity of Liquid Bismuth, Cobalt, Germanium, and Silicon

Assael

Antoniadis

Wakeham

et al. 2017

Journal of Physical and Chemical Reference Data

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The available experimental data for the thermal conductivity of liquid bismuth, cobalt, germanium and silicon have been critically examined with the intention of establishing thermal conductivity reference correlations. All experimental data have been categorized into primary and secondary data according to the quality of measurement specified by a series of criteria. The proposed standard reference correlations for the thermal conductivity of liquid bismuth, cobalt, germanium, and silicon are respectively characterized by uncertainties of 10, 15, 16 and 9.5% at the 95% confidence level.

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Thermal Diffusivities and Conductivities of Molten Germanium and Silicon

Cited by 38 publications

References 14 publications

Solutocapillary convection in germanium‐silicon melts

Solutocapillary convection in germanium‐silicon melts

Thermophysical Properties of Molten Silicon

Reference Correlations for the Thermal Conductivity of Liquid Bismuth, Cobalt, Germanium, and Silicon

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