Morphology and crystalline perfection of InAs films on Si(100)

InAs films were deposited from In and As ₄ fluxes on Si(100) substrates by ion-assisted deposition (IAD). The use of Ar ion irradiation during film nucleation improved the substrate coverage and crystalline perfection. The effect of As ₄-to-In flux ratio r_As and substrate temperature T_s on the nucleation, island coalescence, smoothening, and crystalline perfection of InAs films on Si(100) was studied using reflection high-energy electron diffraction (RHEED), scanning electron microscopy, and X-ray diffraction. Complete substrate coverage was achieved at the lowest film thickness by using r_As ≈ 1 and T_s ≈ 380°C. Continuous InAs films that gave streaky, reconstructed RHEED patterns were obtained at thickness of ≈ 800 nm. It was also found that the presence of anti-phase domains in InAs films led to residual surface roughness in thick films. The typical X-ray rocking curve full width at half-maximum was ≈ 3000 arc sec at a film thickness of 0.4 μm.