Accurate RBS Measurements of the Indium Content of InGaAs Thin Films

Rutherford backscattering is used to obtain absolute compositional data from InGaAs thin films without any reference standards. Carbon-doped InxGa1-xAs thin films with compositions varying between 0.02<x<0.4 have been analysed and values of x obtained with an estimated accuracy of ∽1% in most cases. The observed variation in two measurements of a set of nine samples with a range of values of x has a mean of 1.000 and a standard deviation of 2.2%. This observed error is not inconsistent (at the 5% significance level) with the estimated error. The analytical method described is valid for many compound thin films.