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The vibration–rotation spectrum of the GeH radical for the fundamental band in the 2Π1/2 spin state was observed using an infrared diode laser spectrometer. The GeH radical was produced by ac glow discharge in the mixture of GeH4, He, and H2. The signals were detected by the discharge modulation method. In total 94 GeH lines were identified for five isotopic species, and were simultaneously analyzed to determine effective molecular constants in the 2Π1/2 spin state. [ABSTRACT FROM AUTHOR]

In order to understand the effects of temperature coefficient of surface tension (γT) on oxygen transport as well as on the heater power and the melt/crystal interface shape in a small silicon Czochralski furnace, a set of global numerical simulations is conducted using the finite-element method for a wide range of γT between 0 and 0.35×10−3 N/m K. The results for cases without rotations of crystal and crucible indicate that the larger Marangoni effect enhances a toroidal roll cell in the crucible and reduces the heater power and oxygen concentration in the crystal but makes the melt/crystal interface more convex toward melt. When the crystal and the crucible are rotating in counter directions, an upwelling flow near the axis from the bottom of the crucible takes important role in determining the radial distributions of oxygen concentration. γT gives significant effects on the flow pattern, oxygen concentration, heater power and interface shape. [Copyright &y& Elsevier]

In order to understand the basic characteristics of the gas-phase mass-transfer coefficient (kg) in a small silicon Czochralski (Cz) furnace, a very crude model was proposed and the results were correlated by the Sherwood number as a function of Reynolds number. It was confirmed that by installing a gas guide in the hot zone, the mass transfer coefficient was significantly enhanced. A set of global analyses of small Cz furnaces was conducted with different values of diffusivity of SiO in the gas phase (DSiO) and of oxygen in the melt phase (DO) in order to elucidate which rate process controls the average oxygen concentration ([O]ave) in the grown crystal. These simulations revealed that in these small Cz furnaces, [O]ave is dependent on the gas phase mass transfer rate and melt flow patterns. A decrease in DSiO causes an increase in [O]ave. An increase in DO tends to increase [O]ave slightly in most cases. [Copyright &y& Elsevier]