ELECTROSTATIC LENS WITH SECONDARY ELECTRON DETECTOR FUNCTION

• Main Authors: YAMAZAKI SHIGETOMO, ISHIKAWA AKIO
• Format: Patent
• Language: English
• Published: 13.01.1989
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS; ELECTRICITY

PURPOSE:To increase the secondary electron detecting amount even though the working distance is made shorter by composing a necessary central electrode to form a unipotential type conductive lens, and giving a secondary electron detecting function to it concurrently. CONSTITUTION:A central electrode 11, which composes a unipotential type electron lens together with an upper electrode 1 and a lower electrode 2, is composed of a scintilater 13 to convert secondary electrons e1 into a light, a light guide 12 to transmit the light, a secondary electron detecting device of a photo-electron multiplying tube 15, and a metallic membrane 14 over its surface, while having the secondary electron detecting function concurrently. In such a composition, a separate secondary electron detector is not necessary to furnish between the electrode 2 and the sample 5, for the secondary electrons e1 from the sample 5 generated by the radiation of electron beams (e) from an electron gun 4. And the secondary electron detecting amount is increased even though the working distance between the electrode 2 and the sample 5 is made shorter, and the observation image with smaller lens aberration and with a good image quality can be obtained.