A new method for the estimation of depth profiles of boron in silicon in extremely thin layers by means of neutron induced autoradiography is described. By the aid of ion beam etching it is possible to produce sloping cuts with angles down to 10−4–10−5. This means an extension of the depth profile by a factor of up to 5·104. In this way a depth resolution of about ±10 nm is possible. The autoradiographic model of the sloping cut for the evaluation is described and first results are discussed.