The influence of supercooling on the liquid phase epitaxial growth of inas1−xsbx on (100) GASB substrates

Abstract

The growth by liquid-phase epitaxy of InAs1−x Sb x (x = 0.08-0.16) on GaSb was accomplished by using melts of constant arsenic concentration x As L = 0.014. The study of the influence of the degree of supercooling ΔT on the crystal growth was investigated. The strong tendency of the In-As-Sb liquid to dissolve the GaSb substrate was resolved by using high ΔT (20-30° C) for layers having a positive lattice-mismatch Δa/a more than 1.5 x 10−3. As positive lattice-mismatch becomes smaller, a larger supersaturation is required to control the substrate dissolution. But owing to the bulk nucleation which restricts the supercooling ΔT at values near 30° C, the growth of epitaxial layers with small lattice-mismatch (until - 5 × 10−4) was achieved only from time to time. It was observed that an increase of ΔT increases the concentration of antimony in the epilayers and hence leads to the lattice-mismatch. The dislocation etch pit density was found to be only dependent on the lattice-mismatch. The thickness of the grown layers is proportional to ΔT xt 1/2 with a factorK = 0.025 μm . °C−2 . s−1/2