| 摘要 |
PURPOSE:To reduce a voltage measurement error due to the local field effect and improve the degree of freedom for machining and the assembly precision by forming an extraction grid, a buffer grid, and an analysis grid with disks each having a round hole in the center. CONSTITUTION:An extraction grid G1, a buffer grid G2, and an analysis grid G3 are constituted with disks each having a round hole in the center, the voltage Ve of about 1kV is applied to the extraction grid G1, which serves as an anode for a sample 10 under measurement and extracts upward a secondary electron beam 13 emitted from the sample surface. The voltage VB of about 200V is applied to the buffer grid G2, which serves as an aperture for the secondary electron beam 13 and limits the signal quantity and performs a lens function converging the secondary electron beam 13 into the beam incidence hole of the analysis grid G3. Furthermore, the voltage of about -10-+10V is applied to the analysis grid G3, and its beam incidence hole serves as an energy analysis hole for the secondary electron beam 13. The secondary electron beam 13 thus analyzed is detected by a secondary electron detector 14. |
