| 摘要 |
PURPOSE:To separate and emphasize the shape contrast of a sample by calculating the output ratio between a pair of detectors located at the position symmetrical to the sample and forming an image using this ratio. CONSTITUTION:Secondary electrons emitted with directivity are separated and detected by detectors provided in each direction. A semispherical grid 10 is provided just above a sample 6. This grid 10 is set to ground potential or positive potential (to 50V). Secondary electrons 11 emitted in the right direction advance straight in the emission direction and pass through the grid 10. When the electrons pass through the grid 10, they are absorbed by the voltage applied to a scintilator 4 and are detected by a scintilator 5. Secondary electrons 12 emitted in the left direction are detected by a detector 9. In addition, the ratio between the signals detected in separated directions of the emission is obtained. For example, the signals of the detector 9 are divided by the signals of a detector 8 using a division device 13. As a result, the shape contrast is emphasized. |
