Properties of Vapor Deposited Silicon Nitride Films with Varying Excess Si Content

Abstract

Physical, chemical and electrical properties of Si rich silicon nitride (SiN) film deposited by using the SiH4–NH3 system have been studied. By changing the volume ratio of NH3 to SiH4 from 100 to 1/30, samples with varying excess Si content within SiN films can be obtained. The current conduction mechanism of the SiN film can be represented by the superposition of Poole-Frenkel current, field ionization current and hopping current as reported by Sze in the Si3N4 films without Si excess. Energy levels of trapping centers responsible for Poole-Frenkel current become shallow while their densities remain nearly constant as a function of the Si content. From the dependence of the shift characteristics of C–V curves, it has been deduced that the maximum charge storage within the SiN film is controlled by current conduction through the film.

Deposition and DC electrical characterisation of rf magnetron sputtered silicon nitride thin films

“…The lower temperature value is consistent with a hopping process, probably via centres originating from the Au electrodes, and the increasing slope of the curve with increasing temperature suggests a gradual transition to a free-band process. The free-band process value is in reasonable agreement with values of 0.1-0.35 eV [27] and 0.27-0.36 eV [28] obtained in CVD films. For the higher voltage curves, low-temperature activation energies are similar to those for the 20 mV curve, suggesting that hopping is also dominant in this region.…”

Conduction Studies in Silicon Nitride: Dark Currents and Photocurrents

“…In addition, contact electrode material, silicon nitride thickness, and temperature [8] are varied to explore contact and bulk properties of these MNS structures. It is known [9][10][11] that varying the composition of the Si 3N 4 films changes their conduction properties. The purpose of this study, however, is to examine in detail only amorphous, stoichiometric films.…”

Preparation and Some Properties of Chemically Vapor‐Deposited Si‐Rich SiO2 and Si3 N 4 Films

“…For Si-rich SiO2 films, several articles (5)(6)(7)(8) demonstrate the preparation of these films by sputtering, glow discharge, and evaporation techniques except for a recent paper (9), in which Si-rich SiO2 was prepared by CVD using a SiH4-N20-N~ mixture. The Sirich films exhibited higher conductivity (3,4,9) than the stoichiometric analogs, and the conductivity increased with Si content. Use was made of this variable conductivity property to controllably limit reverse current for a pn-junction diode (9).…”

“…The films are usually amorphous and if the Sill4 is maintained at about 10% or less of the reactive gas mixture, the film compositions are stoichiometric SiO2 or SisN4. It has been reported (1)(2)(3)(4) that the Si content of SisN4 films can be increased for CVD films. In these previous studies, the Si content of the films was inferred from refractive index changes, etch rate measurements, and electrical behavior.…”