Plasma Deposition and Characterization of Thin Silicon‐Rich Silicon Nitride Films

Abstract

Films of Si:,N4 containing excess Si were prepared by plasma-enhanced chemical vapor deposition at 350~ by the glow discharge reaction of gaseous Sill4 (1.9% in helium) in NH:~ in a tube-type, hot wall reactor at 450 kHz RF frequency. The amount of silicon in the Si:,N4 films was adjusted by varying the reactant gas-phase ratio. The deposited films had a refractive index range of 1.90-2.70. Auger analysis (depth profiles) showed -that the Si concentration in the films increased with refractive index. A small amount of oxygen contamination was observed on all film surfaces. X-ray photoelectron spectroscopy measurements showed the presence of excess silicon, probably present as amorphous Si clusters in films with a high refractive index and oxygen contamination in all deposited film surfaces. Fourier transform infrared and nuclear reaction analysis for hydrogen showed that the hydrogen concentration ranged from 13 to 22 atomic percent and the hydrogen concentration decreased monotonically with increased refractive index. Etch rates of deposited films in CF4/O~ glow discharge decrease monotonically with decreased hydrogen and increased silicon concentration in the films.

Hydrogen Diffusion Between Plasma-Deposited Silicon Nitridepolyimide Polymer Interfaces

“…However, in the case of N-H bond density, the variation is somewhat more irregular with temperature, suggesting that Si-H bonds in silicon nitride films are more sensitive to the variation of substrate temperature. This result is also consistent with our previous study on hydrogen bonding and depth-profile variation of plasma silicon nitride deposited at the 25-300* C substrate temperature range [9,10]. We observed no significant changes in total Si-N bond density and vibrational wavelength at this deposition temperature range.…”

“…The presence of hydrogen and its bonding in plasma-deposited silicon nitride films have dramatic effects on physical [7,8] and electrical [9,10] properties of the films.…”

Deposition parameters studies of silicon nitride films prepared by plasma-enhanced CVD process using silane-ammonia

“…Similar results were reported by other workers showing that the increase in flow ratio causes a decrease in etch rate [9,10,12,13]. This ~s due to the fact that the films deposited under high silane conditions have more silicon and less hydrogen and nitrogen content in the film which decreases the etch rate [14].…”

Physical and Electrical Properties of Silicon Nitride and Silicon Nitride‐Indium Phosphide Interface

“…The lineshape is intermediate between gaussian and lorentzian. This discrepancy might be attributed to the formation of silicon clusters which has been reported by Nguyen (10). The linewidth is about 13G, which is about twice as wide as that of amorphous silicon.…”