REMOTE PLASMA-ENHANCED CHEMICAL-VAPOR-DEPOSITION OF SILICON-NITRIDE FILMS - THE EFFECT OF DILUTING NITROGEN WITH HELIUM

SiNxHy films have been deposited using an SiH4-N-2 mixture in a capaci tively coupled remote plasma-enhanced chemical vapour deposition (RPEC VD) system, where conditions favour transport of active species and en ergy to the deposition zone. In contrast to an inductively coupled RPE CVD system, He dilution produces little influence on growth rate. Such a dilution does, however, strongly influence the film composition. He lium atoms promote the formation of atomic nitrogen in the gas phase a nd assist in delivering additional energy to the surface of the growin g film; this leads to changes in the relative amounts of Si-H-i and N- H-j bonds and in the Si/N ratio of the deposited films. With the addit ion of helium, films of composition close to that of stoichiometric si licon nitride can be produced.