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 small liquid free surface at the level of the solid-liquid interface, called liquid meniscus, which creates a gap between the crystal and the crucible. Dewetting phenomenon was first obtained in space experiments during InSb Bridgman solidification performed on Skylab-NASA mission-1974, and subsequently in many experiments carried out in orbiting spacecrafts (microgravity) on a wide variety of semiconductors.rnSince the most important aspect of dewetting is the huge improvement of the crystalline quality (reduction in spurious nucleation, fewer dislocations, lower stresses, etc.), this phenomenon has attracted considerable attention and opened the possibility 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, the static 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 given and compared with experimental data.