Electron-beam-induced conductivity and related processes in insulating films

Abstract

The theoretical model for electron-beam-induced conductivity in thin insulating films is reviewed and its application to gain measurements in several different insulating materials is discussed. The ideas incorporated in the model suggest a technique for investigating trapping levels in insulators, using the electron beam as a means of populating the traps. It is suggested that, in addition to determining the trap eneigy, it may be possible to investigate the spatial distribution of the traps. Electron-beam-radiation effects in SiO 2 are briefly commented upon and the dependence of A Vp^, the shift in flat-band voltage of MOS capacitors, on beam energy is discussed in terms of the gain model. Finally consideration is given to the problem of observing voltage contrast from the passivated devices in a scanning electron microscope.

Fundamentals of electron beam testing of integrated circuits

“…In SiO z , these currents may be 10 to 20 times larger than the primary beam current if a voltage of about 10 V is present between the insulator surface and the metal electrode underneath. The maximum current multiplications with a 1.1~m insulator thickness occur at E pE = 5 keY (10 fold multiplication of electron flow), and at E p E = 15 keV (20 fold multiplication of hole flow) (77).…”

“…If the e-beam completely or partly penetrates a dielectric layer of an IC (e.g. the passivation layer, usually 1 [Am thick) it generates electron-hole pairs in the dissipation volume and causes a current I to flow into the metal electrode underneath the dielectric (23,24,77). In SiO z , these currents may be 10 to 20 times larger than the primary beam current if a voltage of about 10 V is present between the insulator surface and the metal electrode underneath.…”

The effect of the geometry and material properties of a carbon joint produced by electron beam induced deposition on the electrical resistance of a multiwalled carbon nanotube-to-metal contact interface

“…Without an external bias the rest of generated secondary electrons re-equilibrate within the substrate [8]. However, when an external bias is applied the generated electrons can migrate between the electrodes, contributing to the measured electric current [45]. Figure 4 shows the time evolution of measured current during consecutive stages of a deposition process, consisting of building a sequence of overlapping square-shaped carbon deposit blocks to bridge the gap between MWNT and the metal electrode (figure 3).…”