Published online by Cambridge University Press: 22 February 2011
An original process has been developed enabling the fabrication of CVD insulating (Si3N4) thin films, by means of an in-situ activation of the reactions at T < 400°C and under P=1 to 2 torr. Mono-Si substrates were nitrided using a mixture of argon containing SiH4 and NH3·O2 has also been added to the reaction gases. The activation was performed by a DC electrical discharge. The substrate was not used as an electrode and was placed parallel to the discharge current. This configuration minimized the contamination of the films during their formation. The obtained layers have been analyzed using FT-IR and SIMS.
M.I.S. structures have been realized, and the flat-band shift ΔVFB and the interface state density Nit have been extracted from the high and low frequency C-V characteristics. The values of the flat-band shift depend on the discharge domain and decrease with temperature. Good electrical characteristics are obtained for thin films formed at low temperature.