Antiphase domain annihilation during growth of GaP on Si by molecular beam epitaxy

Growing high-quality GaP on Si typically requires a two-step growth process in which the nucleation and overgrowth processes are decoupled. However, even under ideal circumstances, antiphase domains inevitably form during the nucleation step and thus need to be annihilated during the overgrowth step to achieve smooth, single-orientation GaP films. We investigated the effects of V/III flux ratio and growth rate on the propagation and annihilation of antiphase boundaries during the overgrowth step. By enhancing Ga-adatom orientation-dependent surface diffusion, the growth of existing antiphase domains was suppressed by the surrounding film such that the antiphase domains annihilated and yielded a single-orientation film. Characterization of GaP films by atomic force microscopy, transmission electron microscopy, and reflection high-energy electron diffraction shows that certain conditions promoted the annihilation of antiphase boundaries and resulted in smoother films.

► A decoupled two-step molecular beam epitaxial growth process of nucleation and overgrowth was used to grow GaP on Si.
► During overgrowth, any already-existing antiphase domains need to be annihilated to yield high-quality GaP on Si.
► Effects of V/III flux ratio and growth rate on antiphase domain propagation were investigated.
► A low growth rate enhances orientation-dependent Ga adatom diffusion to help antiphase domain annihilation.