Static stability of the menisci in the case of semiconductor crystals grown by dewetted Bridgman technique

摘要

Dewetted Bridgman is a crystal growth technique in which the crystal is detached from the crucible wall by a smallliquid free surface at the level of the solid-liquid interface, called liquid meniscus, which creates a gap between thecrystal and the crucible. Dewetting phenomenon was first obtained in space experiments during InSb Bridgmansolidification performed on Skylab-NASA mission-1974, and subsequently in many experiments carried out in orbitingspacecrafts (microgravity) on a wide variety of semiconductors. Since the most important aspect of dewetting is the huge improvement of the crystalline quality (reduction in spuriousnucleation, fewer dislocations, lower stresses, etc.), this phenomenon has attracted considerable attention and opened thepossibility to reproduce experiments on the earth - obtained by applying a gas pressure difference ΔP= P_(cold)-P_(hot)between the cold and hot sides of the sample. The experiments have shown that using uncoated and coated crucibles,detached and partially detached growth can be obtained. Because our interest is to grow crystals with stable gap, thestatic stability of the menisci in the cases of the classical semiconductors grown in (i) uncoated crucibles (θ_c+α_e<180°),and (ii) coated crucibles (θ_c+α_e ≥ 180°) is studied in zero gravity and terrestrial conditions. Numerical results are givenand compared with experimental data.