Sputter-depth profiling in AES: dependence of depth resolution on electron and ion beam geometry

The precise geometrical relationship between the ion and electron beams and the sample affects the depth resolution of sputter-depth profiles in AES. A theory is presented which predicts this instrumental depth resolution by considering the shape of the ion-eroded crater and the corresponding orientation of the electron beam. The variation in depth resolution is analysed for a range of conditions including (a) varying ion and electron beam diameter (b) the angular orientation of the electron and ion beam and (c) the effect of misalignment of the two beams. (author)