MOVPE growth of BGaAs/GaAs[001], a first step towards BInGaAs

In this study, the B
_x
Ga
_i-x
As/GaAs ternary compound with boron compositions varying up to x = 6 % has been grown by metalorganic vapour phase epitaxy. The incorporation behavior has been studied as a function of growth temperature, diborane flux, gallium precursor and carrier gas. With increasing the growth temperature from 530 to 7OO°C, a maximum of boron incorporation was observed at a growth temperature of 550°C using TEG and 600°C using TMG. Films grown with TMG were obtained under a mixture of nitrogen and hydrogen as carrier gas. Most of the films were mirror-like excepts those obtained at high diborane ratio in the vapor phase (Xv > 0.5). We used trimethylgallium (TMG), triethylgallium (TEG), and diborane as group III precursors. GaAs(001) substrates 1° misoriented towards (110) were used. Double crystal x-ray diffraction was employed to evaluate the boron concentration and the crystalline quality of the layers. The surface morphology was observed by AFM and shows a cross-hatch pattern for the highest boron composition.