We have deposited hydrogenated amorphous siliconhyphen;nitride (ahyphen;SixN1minus;x@B:H) films from NH3hyphen;SiH4hyphen;Ar gas mixtures, heated by gashyphen;phase absorption of CO2laser radiation. For the first time, stoichiometric (Si/N=0.75)ahyphen;Si3N4@B:H films were obtained for NH3/SiH4flow ratios of the order of 1000 and substrate temperaturesTsof about 500thinsp;deg;C. Growth rates as high as 13 Aring;/min were observed, depending on the partial pressure of SiH4,P(SiH4), the gas temperatureTgandTs.Tgwas calculated from a derived energyhyphen;balance equation, which depends sensitively on process parameters. To model the deposition process, the experimental film growth rate is separated into the Si growth rateG(Si) and the N growth rateG(N). Film stoichiometry is interpreted as the ratioG(Si)/G(N). The ratehyphen;limiting steps for Si growth are the gashyphen;phase decomposition of SiH4forTgbelow about 750thinsp;deg;C and the SiH4flow rate at higherTg.G(N) is affected by bothTsandTg. The NH3/SiH4flow ratio must be kept large to ensure a sufficient concentration of N to attain stoichiometry. The reactions are likely to occur both in the gas phase and on the film surface.
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