Techniques for measuring the composition of hydrogenated amorphous silicon-germanium alloys

We grow hydrogenated amorphous silicon-germanium alloys by the hot-wire che mical vapor deposition (HWCVD) technique at deposition rates between 0.5 an d 1.4 nm per second. We prepared a set of these alloys to determine the con centrations of the alloying elements as measured by various techniques. Thi s set consists of samples throughout the range of germanium alloying from 0 % (a-Si:H) to 100% (a-Ge:H). We find that by making the appropriate calibra tions and corrections, our compositional measurements agree between the var ious techniques. Nuclear reaction analysis (NRA), Fourier transform infrare d spectroscopy (FTIR)and secondary ion mass spectrometry (SIMS) all yield s imilar hydrogen contents, within +/-20% for each sample. Electron probe mic ro-analysis (EPMA) and SIMS yield silicon and germanium contents within +/- 7% of each other with results being confirmed by Rutherford backscattering (RBS). EPMA oxygen measurements are affected by oxidized surface layers, th us these data show larger O concentrations than those measured by SIMS. (C) 2000 Elsevier Science B.V. All rights reserved.