Abstract
The thickness (δ) of the transition region of the Si/SiO2 system was derived from backscattering measurements with 600‐kev He ions. Random spectra were interpreted, giving an upper limit δ?50 Å, whereas the aligned spectra indicated some disorder in the interface. This was correlated with concentration gradients of Si and O resulting in a new definition of δ and values from 15 to 50 Å. The number of disordered atoms is about a factor of 2 less for oxides grown on (100) surfaces as compared to substrates with a 〈111〉 orientation.