Sr. Walker et al., MASS AND ENERGY-DISPERSIVE RECOIL SPECTROMETRY OF MOCVD GROWN ALXGA1-XAS, Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment, 353(1-3), 1994, pp. 563-567
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. Ruther
ford Backscattering Spectrometry (RES) has been used extensively in se
miconductor research but overlap of signals in the backscattered ion s
pectrum is an important limitation in the analysis of materials such a
s AlxGa1-xAs which contain elements of low and similar masses. Particl
e 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 situation
s where RES is inappropriate. It employs a heavy ion beam to cause con
stituent nuclei to recoil from the target, and a Time of Flight and En
ergy (ToF-E) detector to detect these recoiling nuclei. Appropriate ma
ss selection of the ToF-E data allows the determination of depth distr
ibutions for each element.