Effect of low-temperature-grown GaSb layer on formation of high-density and small GaSb islands on Si(100) substrate

Abstract

The effect of a low-temperature-grown gallium antimonide (LT-GaSb) layer on the formation of high-density GaSb islands on a Si(100) substrate was studied using ultrahigh-vacuum scanning tunneling microscopy (UHV-STM) and atomic force microscopy. By using an LT-GaSb layer in the initial growth stage (new growth method), high-density and small GaSb islands were formed at 500 °C regardless of the type of the reconstructed surface. The density and size of the GaSb islands with the LT-GaSb layer were estimated to be ∼1.0 × 1011 cm−2 and ∼20 nm, respectively. The STM results showed that the LT-GaSb layer was composed of an Sb-rich amorphous GaSb layer. With a rapid increase in temperature under the Sb flux, the LT-GaSb layer immediately changed into GaSb nuclei with a high density (2.1 × 1011 cm−2) and small size (11 nm). It is suggested that these high-density and small GaSb islands grow from the GaSb nuclei, which act as crystal seeds.