EFFECT OF OXYGEN INCORPORATION OF BHF ETCH RATE OF PLASMA-ENHANCED CVD SILICON NITRIDE FILMS PREPARED IN THE TEMPERATURE RANGE 50-300 degree C.

Abstract

It is shown that oxygen introduction into the reactants during deposition of Si-N films leads to a reduction in the hydrogen content of these films and a reduced etch rate at all deposition temperatures in the range 50-300 degree C. The effect of the hydrogen depletion is more significant at lower temperatures, and this accounts for the etch rate peak at 150 degree C. While the etch rate correlates well with the hydrogen content in the film, the possibility of its dependence on the film structure, as suggested by the density minimum and the sharp change in refractive index at 150 degree C, can not be excluded. 9 refs.