Growth and characterization of high quality B xGa 1− xAs/GaAs(0 0 1) epilayers

Abstract

In a first step towards the growth of BInGaAs, we have grown and characterized the B x Ga 1− x As/GaAs ternary compound with boron composition up to x=0.06 on GaAs(0 0 1) vicinal substrates. The incorporation behavior of boron has been studied as a function of growth temperature, diborane flux, gallium precursor and carrier gas (hydrogen and nitrogen). A maximum for boron incorporation ( x≈0.04–0.06) is found at 550–600°C depending on the precursor and the carrier gas. The epilayers have good crystalline quality as measured by X-ray rocking curve of the (0 0 4) diffraction peak (full-width at half-maximum of 38 arcsec for x=0.035). However, the surface morphology is very sensitive to the diborane supersaturation in the gas phase. At high diborane flow rate, the surface appears as though it is covered in dust. A low surface roughness of 0.4 nm was measured by atomic force microcopy (AFM) in the best growth conditions. AFM images also show a cross-hatch pattern for the highest boron composition.