Improved technique for voltage measurement using the scanning-electron microscope

Further results from experiments designed to lead to quantitative voltage measurements using the scanning-electron microscope are presented. The addition of a simple 2-electrode accelerator system to the Everhart-Thornley secondary detector changes the voltage characteristic of the detector so that it can be approximately defined in terms of the potential of the point at which the primary beam reaches the specimen. The results demonstrate that the improved characteristic allows a control-loop arrangement, described in a previous letter, to be used for quantitative observation of applied potential distributions with the scanning-electron microscope.