CHARACTERIZATION OF INTRINSIC STRESSES OF PECVD SILICON NITRIDE FILMS DEPOSITED IN A HOT-WALL REACTOR

K. Aite , R. Koekoek , J. Holleman , J. Middelhoek

Intrinsic stresses in PECVD silicon nitride films can cause failure to occur both during device processing and in service. The relevant deposition parameters influencing the intrinsic stresses of the plasma deposited silicon nitride films have been investigated. Emphasis is given to the parameters which were superficially or never reported in the literature. The silicon nitride films were deposited on 4-inch silicon substrates from SiH4 and NH3 with or without N2 in a horizontal hot-wall reactor with a multielectrode system. The temperature of deposition was typically 350 °C and the rf frequency 50 kHz. It is shown that the intrinsic stresses (σi) of plasma silicon nitride films decrease exponentially with the total gas pressure (P) of the glow discharge, following the relation : σi = 24.7 exp(-1.265.P). The intrinsic stresses of the PECVD silicon nitride films increase linearly with the nitrogen incorporation into the gas mixture and depend on the SiH4/NH3 gas ratio. With increasing the interelectrode distance, the intrinsic stresses of the plasma nitride layers decrease. It is further shown that there is no correlation between the intrinsic stresses and the hydrogen content of the plasma silicon nitride films. The mechanical stresses in the films were determined by the Newton's fringes technique and a surface profiler. The film thickness was measured by ellipsometry at a wavelenght of 632.8 nm. FTIR spectroscopy was used to measure the hydrogen content of the plasma nitride films.

Domaines: Articles anciens

K. Aite, R. Koekoek, J. Holleman, J. Middelhoek. CHARACTERIZATION OF INTRINSIC STRESSES OF PECVD SILICON NITRIDE FILMS DEPOSITED IN A HOT-WALL REACTOR. Journal de Physique Colloques, 1989, 50 (C5), pp.C5-323-C5-331. ⟨10.1051/jphyscol:1989539⟩. ⟨jpa-00229562⟩