Patent ID: 7205534

Claim:
Method for modifying electronic properties of a sample surface to analytical ends, comprising in situ deposition of neutral cesium (Cs 0 ), under ultra-high vacuum, said neutral cesium being enabled in the form of a collimated adjustable stream, said Cs 0 deposition being simultaneously accompanied by a primary bombardment of said surface, in the form of at least a beam comprising electrons and/or ions or neutral atoms or groups of atoms, or by an X-ray irradiation, intended to induce a secondary emission or sputtering of particles for analysis, out of the surface, said sputtering comprising secondary electrons and/or Cs x n+ and/or MCs x n+ positive clusters (x=1, 2) and/or M n− negative ions and/or M m+ positive ions, M being a constituent of the sample material made of an atom or a group of atoms (n, m integers), the Cs 0 deposition being decoupled from the primary bombardment conditions, to provide a simultaneous optimization of deposited Cs 0 concentration and analytical characteristics, such as the depth resolution, characterized in that said optimized deposited Cs 0 concentration is chosen only by adjusting the ratio (τ=V er /V D ) between the erosion rate (v er ) and the Cs 0 deposition rate (V D ), for a given sample and given primary bombardment conditions.