Low Temperature Deposition of Silicon Nitride by Reactive Ion‐Beam Sputtering

Abstract

The deposition mechanism of reactive ion beam sputtered silicon nitride was studied. Using RBS analysis, the composition of SixN~ layers deposited at room temperature has been investigated as a function of different parameters. Irrespective of the nitrogen partial pressure, ranging from 10 _4 to 0.2 Pa, the stoichiometry of the film depends only on the sputtering yield of silicon in the range 0.4-20 keV. Si3N4 layers can be obtained at low voltage, but only with a low deposition rate (typically I nm/min at our experimental conditions). In order to obtain Si3N4 films with higher deposition rates, we increased the nitridation of deposited silicon, either by introducing in the deposition chamber a highly reactive molecule such as NH3, or by using electronic bombardment, which stimulates the adsorption of N2 on the growing film.

Mechanisms of Reactive Ion‐Beam Sputtering of Silicon Nitride in Presence of 15N‐ or D‐Labeled Ammonia

“…Deposition.--The experimental setup used for the present study has been described elsewhere (1,2). It has been improved by including a beam profile monitor, which enables us to check the current density of ions impinging the target.…”

“…In a previous paper (1), we have studied the variations of the composition of SixN, layers deposited by reactive ion-beam sputtering at room temperature, as a function of different parameters. The film composition has been found to depend only on the N~ ~ ion-beam energy and not on the nitrogen partial pressure.…”

“…The deposition mechanisms that may be considered to explain the composition of reactive ion-beam sputtered Si~N~ films have been previously discussed (1). Only the reactions that may occur on the surfaces of the target and the growing film have to be taken into account because, during our experiments, the total pressure always remains sufficiently low to insure that the mean free path of sputtered atoms or molecules is very large with respect to the distance between the target and the substrate.…”

“…(iii) Ammonia and molecular nitrogen may be adsorbed on the growing film. The sticking coefficient of molecular nitrogen on SijN~ being very low (1), only the case of ammonia adsorption will be examined.…”

Croissance de Si3N4 sur GaAs et InP par pulvérisation réactive par faisceau d'ions

“…Une expérience de croissance de nitrure de silicium a été effectuée avec une énergie ionique de 1 keV. Le dépôt ainsi obtenu est sous-stoechiométrique (N/Si = 0,9) [38,39]. On constate alors que l'atténuation des signaux Auger du gallium et -de l'arsenic est conforme à une croissance couche par couche et que le rapport As/Ga n'est pas affecté.…”