Amorphous Si3N4 containing uniformly distributed carbon was prepared by chemical vapour deposition [Am. CVD-(Si3N4-C)] using SiCl4 vapour and NH3, H2 and C3 H8 gases at deposition temperatures (Tdep) of 1100 to 1300° C and at total gas pressures (Ptot) of 30 to 70 torr. The density of Am.CVD-(Si3N4-C) is between 2.80 and 3.00 g cm-3, depending upon the deposition conditions. Rate of growth in thickness increases with increasing Tdep and Ptot, and has the largest value of 0.6 mm h-1 at Tdep=1300° C, Ptot=70 torr and propane gas flow rates [FR(C3H8)] of 0 to 20 cm3 min-. The activation energy of the formation decreases from 38 to 20 kcal mol-1 with increasing Ptot and FR(C3H8).
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