A new approach for dopant distribution and morphological stability in crystals grown by the axial heat processing (AHP) technique

A comparative study on the growth of germanium–silicon single crystals grown by the vertical Bridgman and axial heat processing techniques

“…In contrast, a decreased radial segregation with a decrease in melt height is not observed for the AHP grown crystals with 2 mm/h pulling velocity. This is not too much of a surprise because when the pulling velocity increases, strength of the forced flow increases, as well [22,24]. Therefore, when the melt height in the AHP growth is lowered to 5 mm from 10 mm, the forced flow disturbs the growth domain leading to segregation.…”

“…While buoyancy forces are generated due to natural convection, forced flow is brought about by the differential motion of the crucible and the baffle [24]. Buoyancy forces, proportional to the dimensionless Ra number, are dominantly observed to cause mixing in the vertical Bridgman type growth.…”

“…Three models, constitutional supercooling (CS) [29], MullinSekerka's (MS) perturbation theory [30], and AHP back-diffusion model [24], are used to investigate the interface stability in crystals grown in this current study. The CS and MS models are developed for crystal growth with pure diffusional mixing mode and having constant growth velocity, whereas AHP back-diffusion model considers both diffusional and convectional mixing effects.…”

“…In fact, one should not expect these equations to predict the instability in this case since both of them are derived for the pure diffusional systems under the steady state growth conditions. However, the solute transportation in the samples is partial mixing [24] and the growth is not in the steady state condition. Hence, AHP backdiffusion model is used to predict the interface stability.…”

Melting and homogeneity in germanium–silicon alloys and a modified micro-manufactured assembly for stable high pressure and temperature measurements

“…While the silicon-rich side of the phase diagram is more accessible, because the segregation coefficients are smaller than those for germanium-rich starting compositions, homogeneous reaction products are a challenge throughout. [3] Silicon and germanium are stable in the cubic diamond structure to about 10 GPa. [4] Within this pressure regime, their melting points decrease [5,6] as a function of pressure because the liquids are denser than the solids.…”