IP-1 Optimization of Secondary Electron Detection by Segmental Ionization Detector in Environmental SEM.

Environmental scanning electron microscope differs from the conventional one in the presence of a specimen chamber gaseous environment that enables direct observation of electrically insulating or liquid-phase containing specimens [1], [2]. Secondary electron (SE) detection by a conventional E-T detector located in the specimen chamber is not possible due to the gaseous environment of the pressure range from several tens to several thousands Pa. Therefore, an ionization detector (ID) is usually used. The ID utilizes signal amplification in the process of impact ionization in an electrostatic field created by a positive bias on a detector electrode and a grounded specimen [2]; the specimen can be also a few V biased. In the previous work, signal detection by an ionization detector with a varied electrodes geometry and varied voltages on these electrodes was studied [3], [4]; the detector was named segmental ionization detector (SID). The SID position in the specimen chamber is shown in Fig. 1