Conductivity Induced by Electron Bombardment in Thin Insulating Films

Abstract

It is surprising that the assumption that all scattered quanta of one group have the same energy yields results so closely in agreement with experiments on both intensity and spectral distribution of the radiation. The meaning of this assumption in terms of the energy distribution is illustrated in Fig. 7, in which the number of quanta with energy greater than E has been plotted. This number increases by N whenever F. passes through one of the energies EI". . The same number has been computed from a statistical study of 200 calculated y-ray tracks by Dr. Fano and Mr. Karr at the National Bureau of Standards and is also shown in Fig. 7. The similarity of the two curves accounts for the close agreement between our experimental and calculated results.'Ke are indebted to Dr. Fano and Mr. Karr for permission to quote the results of their work on an OfFice @&hen thin films of insulating material are bombarded by high velocity electron beams that can penetrate through the thickness of the film, steady currents can be obtained that are as much as 100 times that in the bombarding beam. These currents vary with the gradient across the film and are proportional to the fraction of the beam energy absorbed in the film. Typical data obtained with amorphous silica are presented, together with a description of the experimental procedures that were used. v ere prepared by heating the plates in .in;itniosphere of ethyl silicate vapor, which (Iecon&poses

Charge collection scanning electron microscopy

“…Although the study of electron bombardment effects in dielectric films predates charge collection studies in semiconductors (McKay 1948(McKay , 1950Pensak 1948;Ansbacher and Ehrenberg 1950), the advent of metal-oxide-silicon (MOS) technology was required to stimulate significant further work in this area. Indeed, the great bulk of experience here is limited to one system, Al-Si0 2 -Si, and our discussion will be confined to this case.…”

Electrical current distribution across a metal–insulator–metal structure during bistable switching

“…Performing EBIC in a SEM provides a way to map and quantify the inhomogeneities in the electrical properties of a material that are due to several types of intrinsic defects. Since the pioneering work of Pensak [22], to our knowledge, very few EBIC studies have been done on MIM structures, such as ours, using an insulating oxide epitaxially grown on a metallic oxide base electrode. The diagram of the experimental arrangement is shown in Fig.…”

AN IRRADIATION EFFECT IN THERMALLY GROWN SiO2

“…The conditions that in general determine the surface potential of a dielectric film that is bombarded with electrons have been described by Pensak. 1 The combined secondary electron, backscattered electron, and induced conductivity must balance the incident current. Pensak used a second low-energy beam to discharge the surface.…”

“…1 The conditions for the appearance of a negative space charge are different from those necessary to give a positive space charge as reported by some other workers. 3 ,6-a Thus, Grove and Snow 7 describe a model in which a positive space charge is formed close to the negative oxide surface because (1) hole-electron pairs are generated by the irradiation; (2) the electrons are more mobile than 6 11= \' the holes, and (3) additional electrons cannot enter easily into the oxide to neutralize the positive space charge that is formed close to the negative surface.…”