Twins in GaAs Crystals Grown by the Vertical Gradient Freeze Technique

Abstract

The growth of facets and the generation of twins on (100) VGF (vertical gradient freeze technique) grown GaAs were investigated using DSL (diluted Sirtl-like etchant with light) photoetching and transmission X-ray topography. Due to the polarity of the (1 11) plane in GaAs, As facets are larger and more irregular than Ga facets and twins always occur on As facets. Twins are initiated at the change of boundary condition which IS affected by temperature gradient and crucible shape. The mechanism of twin generation is explained by considering the edge concavity at the solid-liquid interface and the supercooling required for initial nucleation of a facet. Twins are more often produced in Si-doped crystals than undoped ones due to the constitutional supercooling.

Industrial growth and characterization of Si‐doped GaAs crystal by a novel multi‐crucible Bridgman method

“…GaAs crystal has zinc‐blende structure, (111)As and (111)Ga edge facets would continual generate during the whole growth procedure due to their polarity behavior, as a result, the formation of twinning in GaAs crystal might happens regardless whatever growth methods are employed . The twinning problem could be induced by several factors according to the formula D = ΔT/(g.cosθ) , where D is facet size, ΔT the supercooling, g the axial temperature gradient, and θ the angle between solid‐liquid interface and crucible wall . In this experiment, it is concluded the θ value might be the main reason causes the formation of twinning.…”

Study on polycrystallization in bulk InxGa1−xAs using micro-Raman and photoluminescence

“…In previous studies [7][8][9][10], several reasons for the polycrystallization mechanism in III-V semiconductor ingots were discussed. However, they only justify the initiation of polycrystallization near the peripheral region of the ingots.…”

“…It is usually observed that polycrystallization during growth process starts at the periphery of the sample near the crucible, which is commonly correlated with factors such as temperature gradient [7] and temperature fluctuation [8] at the solidliquid interface, the growth facets [8], the shape of the interface [9], the purity of raw material and cone angle of the crystal [10]. In the present study, we investigate the polycrystallization in bulk In-…”

Dislocation formation in heavily As‐doped Czochralski grown silicon

“…In literature it was shown that during the growth of InP the interruption of large facets led to the formation of twins . Although, twin formation is a common phenomenon for III‐V semiconductors, it is negligible for CZ growth of Si, since the risk for twinning is proportional to the ionicity and inverse proportional to the stacking fault energy and the stacking fault energy is highest in Si . Therefore, a more detailed view on the growth of these facets is necessary to clarify their influence on the risk of dislocation formation in heavily n‐type doped Si.…”