On the Conduction Mechanism of Silicate Glass Doped by Oxide Compounds of Ruthenium (Thick Film Resistors)

Abstract

ABSTRACT

On the Conduction Mechanism of Silicate Glass Doped by Oxide Compounds of Ruthenium (Thick Film Resistors). 3. The Minimum of Temperature Dependence of Resistivity

“…As reported earlier [2] the nanocrystals of silicates in the glass and narrow impurity band formed in firing process can explain the experimental [3] [4] low-temperature resistance of DSG in the form…”

“…It is very important here to note that the impurity band-gap is narrow (about tens of meV) as the electron-phonon coupling constant has small value. So the band-gap can vanish at temperature T m near the room temperature (the broad brand-gap will disappear at high T m and we can't observe its vanishing due to the structural transitions of nanocrystals [2]). Thereafter the joined partially filled valence band is formed in the DSG, the concentration of the free carriers n(T) becomes constant and the resistivity of the DSG will be affected by temperature due to electron-phonon or electron-electron scattering only so R(T) ~ T or R(T) ~ T 2 as in the typical metals.…”

“…The diffusion mechanism allowed us to explain shifting of the percolation threshold towards to lower value and the effect of firing conditions as well as the components composition on the electrical conduction of the doped glass (DSG). The coexistence of thermal activation and localization of free charge carriers as the result of nanocrystalline structure of the glass was the subject of the second part [2]. Because of it, the resistivity of the doped silicate glass is proportional to exp (-aT -ζ ) at low temperatures (T < 50 K), 0.4 < ζ < 0.8.…”

“…In the first part [1], the formation of percolation levels due to diffusion of dopant atoms into the glass has been considered. The diffusion mechanism allowed us to explain shifting of the percolation threshold towards to lower value and the effect of firing conditions as well as the components composition on the electrical conduction of the doped glass (DSG).…”

Evolution of Conduction Mechanism in Thick Film Resistors.

“…Abdurkhmanov [21] from his studies on conduction mechanism in thick film resistors formed by silicate glass doped with ruthenium oxides proposed formation of diffusion zones around the dopant particles in the softened glass during firing of printed resistors due to which doping glass would become conductive. He attributed the conduction in the fired films to these highly conductive zones which act as percolation levels for for free charge carrier movement.…”