Quaternary InxGa1-xAsyN1-x(x > 0.53, 1 - y < 0.03) QWs grown between In0.52Al0.48As barriers on InP substrate were analyzed by SIMS depth profiling. For the determination of the indium and nitrogen calibration curves, InxGa1-x As (0 less than or equal to x less than or equal to 1) standards were used which were partly implanted with nitrogen at an energy of 75 keV and a dose of 5 x 10(15) N-2 molecules/cm(2). The QW structures were grown by molecular beam epitaxy with a nitrogen plasma source. MCs+ secondary ions (M = Al, Ga, In, As and N) were used for depth profiling. Nitrogen is found incorporated in InxGa1-xAs layers in concentrations needed for the intended laser applications. The nitrogen concentration can be reliably assessed by SIMS. Thickness and compositional data agree with the nominal data and the data determined by high resolution X-ray diffraction. The In-content is apparently not influenced by the incorporation of nitrogen and vice versa. (C) 2002 Elsevier Science B.V All rights reserved.