The crater edge formed in Si‐SiO2films by appropriate ion‐beam etching provides an angle‐lapped surface analogous to that produced by usual mechanical means; however, the angle can be usefully reduced by 3 orders of magnitude, allowing much greater spatial resolution. Furthermore, in contrast to conventional depth profiling, the separation of the etching and analysis permits repetitive measurements to be made conveniently; a fact of considerable utility in interface analysis.