The DC and RF resistivity of discontinuous metal films: a size effect theory

Abstract

A model based on the Mayadas-Shatzkes theory of polycrystalline films is proposed to represent discontinuous films in which island boundaries are considered to be partially reflecting planes, the coefficient of reflection at the boundaries being equivalent to the energy associated with charge transfer from one island to the neighbouring one. The relation between DC resistivity and the thickness of discontinuous films is discussed, and a quantitative picture is presented. The resistivity at radio frequencies, at which islands are effectively AC-shunted, is also considered. The coefficient of reflection at these frequencies is significantly different from that for DC measurements, and its value depends on the nature of the crystallinity of the islands.Thickness-dependent DC and RF resistivities of polycrystalline, discontinuous bismuth films have been studied, and the results are presented. The agreement of the data with our model is quite satisfactory.

Organophosphorus compound detection with a supported copper + cuprous oxide island film. 2. Alternating current studies and sensor performance

“…It has been known since the 1930s that very thin, evaporated metallic films exhibit a decrease in resistance as the frequency of the applied potential increases (3,4). This behavior is physically attributed to the presence of interisland capacitance, whose impedance decreases with increasing frequency (5)(6)(7)(8)(9)(10)(11)(12)(13)(14). In an effort to interpret this phenomenon, the interisland capacitance has been modeled as a continuous distribution (5, 6), as a discrete parameter (7), and as a mixture of the two (8).…”

“…In an effort to interpret this phenomenon, the interisland capacitance has been modeled as a continuous distribution (5, 6), as a discrete parameter (7), and as a mixture of the two (8). However, unless a film is ultrathin (<30 A), it has been shown that the effect of distributed capacitance on the frequency-dependent resistance is negligible (9). This behavior is manifested because the interisland capacitance, corresponding to the separation between large islands, predominates.…”

“…First-order calculations by numerous investigators (9)(10)(11)(12)(13)(14)(15) reveal that a very simple, lumped-parameter equivalent circuit 0003-2700/88/0360-1737$01.50/0 proposed by Chasmar (7) is quite adequate for characterizing measured results. The equivalent circuit is illustrated in Figure 1.…”

“…Most of the impact of NMR in chemical analysis has, until rather recently, been based on NMR signals of species in liquid samples. During the past few years, the advent of such line-narrowing techniques as magic-angle spinning (MAS) has extended the analytical applicability of NMR to a wide range of solid samples (8)(9)(10)(11)(12).…”

“…For cases of isotopically or spatially dilute spin-1/2 nuclides, e.g., 13C, 29Si, 16N, and 31P, the main obstacles to obtaining high-resolution NMR spectra of solids have been inefficient spin-lattice relaxation, dipolar interactions between the dilute nuclei and protons, and chemical shift anisotropy (CSA). These influences are now routinely overcome by cross polarization, high-power proton decoupling, and magic-angle spinning, respectively (8)(9)(10)(11)(12). These same kinds of techniques have also proven to be useful in obtaining relatively sharp NMR peaks from the central transitions of nuclei with n/2 spin, where n is an odd integer, e.g.,27A1 (9,13,14).…”