Inspection of passivated microdevices using the scanning electron microscope (SEM) at a low primary electron energy has been increasingly studied. Previously we reported an empirical formula for conditions under which SEM observations over the passivation layer can be made without inducing serious charging disturbances. An investigation of charge balance between primary and secondary electrons was presented. The present work investigates the charging disturbance-free conditions of PSG, SiN, and Si3N4 passivated devices and how they are affected by beam irradiation. The storage time of the voltage contrast is measured for various values of primary electron energy and incident angle.