Nitrogen incorporation into GaAs(N), Al0.3Ga0.7As(N) and In0.15Ga0.85As(N)by chemical beam epitaxy (CBE) using 1,1-dimethylhydrazine

Nitrogen incorporation in the growth of epitaxial GaNxAs(1-x) by chemical b eam epitaxy (CBE) using 1,1-dimethylhydrazine (DMHy) was compared, for the first time, when using each of 2 sources of arsenic. Each of cracked arsine (AsH3) and uncracked tris(dimethylamino) arsine were used with triethylgal lium as Group III source, at a growth temperature of 490(+/-5)degreesC. Dif ferent incorporations were found at high flow pressures of DMHy in the two cases. Nitrogen compositions of fully-strained GaNxAs((1-x)) epilayers from 0.01% to 4.2% were measured by X-ray diffractometry (XRD) on the assumptio n that Vegard's law applies. Higher nitrogen compositions, up to 7(+/-2)%, were measured by cross-sectional high resolution electron microscopy (HREM) to yield structural information and a measurement of the lattice parameter . Collation of the secondary ion mass spectrometry (SIMS), XRD and HREM dat a showed that there is good agreement between the nitrogen composition infe rred from the lattice parameter and the chemical content, suggesting that t he nitrogen is incorporated substitutionally in GaNxAs(1-x) grown under the se conditions by CBE. Using trimethylindium and ethyldimethylaminealane wit h AsH3 and TEGa, the nitrogen incorporations into both 15% InGaAs and. for the first time. into 30% AlGaAs were also measured. Distinctly different ni trogen incorporation efficiencies were observed for the three alloys. parti cularly at high nitrogen percentages. Unintentional hydrogen incorporation was measured by SIMS for layers grown with AsH3 and found to be at around 1 0% of the nitrogen level for all three alloys studied. Crown Copyright (C) 2001 Published by Elsevier Science B.V. All rights reserved.