| 摘要 |
PURPOSE:To obtain the voltage contrast even if the potential range of the subject will vary in any way, by deflecting the locus of the secondary electron emitted from the subject by means of a pair of electrostatic electrodes provided above and below said locus. CONSTITUTION:The secondary electron beams 6, 7 emitted from a subject upon irradiation of the electron beam 1 will fly toward a secondary electron detector 5. A pair of electrostatic electrodes 8 are provided in the proximity of the locus of the secondary electron beams 6, 7 then the constant voltage corresponding with the potential range of the subject 2 is applied on said electrode 8 to deflect the flying direction of the beams 6, 7. Consequently even if the potential range of the subject 2 is varied in any way, its voltage contrast can be obtained. |
