Growth and characterization of high quality BxGa1-xAs/GaAs(001) epilayers

In a first step towards the growth of BInGaAs. we have grown and characterized the BxGa1-xAs/GaAs ternary compound,with boron composition up to x = 0.06 on GaAs(001) 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 approximate to 0.04-0.06) is found at 550-600degreesC 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. (C) 2002 Elsevier Science B.V. All rights reserved.