Imaging deep trap distributions by low vacuum scanning electron microscopy

The distribution of deep traps in a bulk dielectric (Al2O3) is imaged by low vacuum scanning electron microscopy (LVSEM). The image contrast corresponds to spatial variations in radiation-induced, field-enhanced conductivity. A methodology is presented for identification of such contrast, the behavior of which is explained by a model of charge generation and transport in dielectrics imaged by LVSEM. The technique presented is applicable to studies of charge traps in dielectrics, device failure modes, and contrast mechanisms in electron microscopy.