BxGa(1-x)As alloys have been grown by molecular beam epitaxy. Reducing growth temperature below 540degreesC and increasing the V/III flux ratio above 20 improved boron incorporation in the epitaxial layers while preserving crystal quality. Higher growth temperatures and lower V/III ratios lead to significant amounts of B incorporation on interstitial lattice sites. With optimized growth conditions, pseudomorphic BxGa(l -x)As films with x = 0.078 have been grown with good crystal quality and no detectable interstitial B incorporation. (C) 2004 Elsevier B.V. All rights reserved.