BONDED HYDROGEN IN SILICON-NITRIDE FILMS DEPOSITED BY REMOTE PLASMA-ENHANCED CHEMICAL-VAPOR-DEPOSITION

Using FTIR the hydrogen content of silicon nitride films grown by remo te plasma-enhanced CVD (RPECVD) has been quantitatively examined, The influences of process parameters on the concentration of bonded hydrog en and on its nature are discussed. It is suggested that the incorpora tion of Si-H bonds is largely determined by gas-phase processes while that of N-H bonds arises from surface interactions. The preferential t ype of hydrogen bonding to silicon is found to occur as Si-H-2 whereas for nitrogen N-H appears to be the most likely form of bonding. The t otal hydrogen content of capacitively coupled RPECVD films is found to be only ca. 9 x 10(21) cm(-3) at a growth rate ca. 20 times that obta inable by inductively coupled RPCEVD. Therefore there is considerable potential for depositing films with very low total hydrogen content by capacitively coupled RPECVD.