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Summary: Germanium partitioning in silicon during rapid solidification
D. P. Bruncoa) and Michael 0. Thompson
Department of Materials Science and Engineering, Cornell University Ithaca, New York 14853
D. E. Hoglund and M. J. Aziz
Division of Applied Sciences, Harvard University Cambridge, Massachusetts 02138
H.-J. Gossmann
AT&T Bell Laboratories, Murray Hill, New Jersey 07974
(Received 3 October 1994; accepted for publication 11 April 1995)
Pulsed laser melting experiments were performed on Ge,Sir-, alloys (x60.10) with regrowth
velocities ranging from 0.25 to 3.9 m/s. Analysis of post-solidification Ge concentration profiles,
along with time-resolved melt depth measurements, allowed determination of the liquid-phase
diffusivity Dt for Ge in Si and the dependence of the Ge partition coefficient k on interface velocity
u . A Dt of 2.5X lo-" cm"/s was measured. The k vs v data were analyzed using various models for
partitioning, including both the dilute and nondilute Continuous Growth Models (CGM).
Extrapolating to zero velocity using the partitioning models, an equilibrium partition coefficient of
approximately 0.45 was obtained. Best fitting of partitioning data to the nondilute CGM yields a
diffusive speed of 2.5 m/s. These measurements quantify previous indications of partitioning
observed in other studies of pulsed laser processed Ge$+ --x alloys. 0 1995 American Institute of
Physics.
I. INTRODUCTION
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