Mass and energy dispersive recoil spectrometry of MOCVD grown AlxGa1-xAs

Mass and energy dispersive Recoil Spectrometry (RS) has been employed to study stoichiometric variations in AlxGa1-xAs layers. Quantitative determination of x is an important problem in the production of device materials which is not easily solved with standard techniques. Rutherford Backscattering Spectrometry (RBS) has been used extensively in semiconductor research but overlap of signals in the backscattered ion spectrum is an important limitation in the analysis of materials such as AlxGa1-xAs which contain elements of low and similar masses. Particle Induced X-ray Emission (PIXE) analysis has good elemental resolution for this class of materials but provides little depth resolution. RS enables the determination of separate energy spectra for individual or small groups of isotopes. This allows it to be used in many situations where RBS is inappropriate. It employs a heavy ion beam to cause constituent nuclei to recoil from the target, and a Time of Flight and Energy (ToF-E) detector to detect these recoiling nuclei. Appropriate mass selection of the ToF-E data allows the determination of depth distributions for each element. ((orig.))