A novel method of semiconductor device measurements

Electrical signals induced in semiconductor devices by a high-resolution scanning electron beam have been used to determine the boundaries of doped (p or n) regions, even when these boundaries lie beneath passivating oxide layers, or beneath evaporated metal leads. The uniformity of planar junctions lying beneath the device surface can also be ascertained by this method, and the junction depth can be estimated by comparing measurements made at different electron-beam voltages. The spatial resolution of this technique is limited by the penetration and scattering of electrons in the device material; these scattering effects are discussed, and representative micrographs showing resolutions of a few microns are presented, as well as various quantitative measurements related to the method.