| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for activating a scanning transmission electron microscope (STEM), in which a sample (1) is scanned with the use of an electron focused beam (2), the diameter of the cross-over (3) can be 0.1 nm or smaller, as known to the person skilled in the art, the diameter of the cross-over depends on the opening half-angle α of the beam, therefore an opening half-angle is chosen so that the diameter of the cross-over R(α) shows the minimum for obtaining an optimum resolution, for thick samples, the resolution for those parts of the sample apart from the cross-over plane is limited by the convergence of the beam, resulting in a diameter D of the beam at the surface of the sample. SOLUTION: The opening angle is chosen to balance the contribution of convergence and of diameter of the cross-over by choosing an opening half-angle smaller than the optimum opening half-angle. The sample is then scanned with the use of a beam that has a substantially constant diameter over the length of the sample material through which the electrons have to travel. COPYRIGHT: (C)2009,JPO&INPIT |
