Epitaxial GaSb films directly grown on on-axis Si(001) with low defect density by MBE

Abstract

In recent years, GaSb-on-Si direct heteroepitaxy has been highly desirable to extend the operating wavelength range into mid-infrared and high-mobility applications, such as free-space communications, gas sensing, and hyperspectral imaging. High-quality GaSb films on Si remain challenging due to the high density of defects generated during the growth. For this purpose, epitaxial GaSb films were grown by molecular beam epitaxy on on-axis Si(001). Due to the large lattice mismatch (12.2%) between GaSb and Si, here, we proposed a radical design and growth strategy with the primary objective of achieving the annihilation of antiphase boundaries (APBs) and the reduction of threading dislocation density (TDD). Benefitting from a V-grooved Si hollow structure, we demonstrated the growth of emerging-APB-free GaSb film on Si(001) with low mosaicity. Moreover, by introducing InGaSb/GaSb dislocation filtering layers, the atomically flat surface root mean square roughness is improved to 0.34 (on Si) and 0.14 nm (on GaAs/Si). Moreover, the corresponding TDD can be reduced to 3.5 × 107 and 2 × 107 cm−2, respectively, one order of magnitude lower than the minimum value found in the literature. These reported results are a powerful lever to improve the overall quality of epitaxial Si-based antimonide, which is of high interest for various devices and critical applications, such as laser diodes, photo-detectors, and solar cells.