Ultra Low Voltage Imaging with Hitachi's S-4800 FE-SEM

Field emission SEMs are used primarily for their performance at low voltage. The brightness of the source provides the much needed signal for high-resolution secondary electron imaging. Microscopists often work in this region to see such benefits as fine surface detail and minimal specimen charging. The aim of the operator is to attain charge balance; the electrons going into the specimen equal the electrons leaving the specimen. Past work has been done to attain the E2 or second charge balance position, mainly because the E1 positions were below traditional accelerating voltage levels. The Beam Deceleration Technology on the Hitachi S-4800 makes the E1 position of charge balance within reach. Operating between 100 volts and 2kV while using the Beam Deceleration technology not only achieves the ideal E1 landing voltage (voltage of the primary beam at the sample) but also applies the aberration coefficients of the higher initial accelerating voltage thus resulting in improved resolution.