Detection of BSE in the low voltage SEM with an electrostatic immersion lens and a field-free specimen

摘要

Detection of backscattered electrons in the scanning electron microscope equipped with an electrostatic retarding lens was studied theoretically and experimentally. The primary beam after retardation by the lens impinge on the specimen held at the potential close to the potential of the lower electrode of the lens. Low take-off backscattered electrons move initially in a field-free space and after acceleration are detected by a ring scintillation detector. Theoretical studies included analytical and numerical computations of electron-optical parameters of the retarding lens. Next, different configurations of low-voltage detectors were tested experimentally in the scanning electron microscope.