Effect of graded-temperature arsenic prelayer on quality of GaAs on Ge/Si substrates by metalorganic vapor phase epitaxy

Abstract

The growth of GaAs epitaxy on Ge/Si substrates with an arsenic prelayer grown with graded temperature ramped from 300 to 420 degrees C is investigated. It is demonstrated that the graded-temperature arsenic prelayer grown on a Ge/Si substrate annealed at 650 degrees C not only improves the surface morphology (roughness: 1.1 nm) but also reduces the anti-phase domains' (APDs) density in GaAs epitaxy (dislocation density: similar to 2 x 10(7) cm(-2)). Moreover, the unwanted interdiffusion between Ge and GaAs epitaxy is suppressed by using the graded-temperature arsenic prelayer due to the low energy of the Ge-As bond and the use of a low V/III ratio of 20. (C) 2011 American Institute of Physics. [doi:10.1063/1.3656737]