Formation of high moisture and dopant diffusion resistivity silicon nitride films by catalytic-CVD method

Abstract
High resistivity for moisture and dopant diffusion silicon nitride films are prepared by catalytic-CVD method. In this method, SiH₄ and NH₃ gases are decomposed by the catalytic-cracking reactions with a heated tungsten catalyzer placed near substrates, and so that silicon nitride films are formed without any help from plasma nor photochemical excitation at the temperature as high as 300°C. The properties of catalytic-CVD silicon nitride films are investigated. It is found that, 1) stoichiometric silicon nitride film whose refractive index is 2.0 shows high moisture resistance, 2) ultrathin silicon nitride film (equivalent oxide thickness: 3.5nm) blocks B diffusion even 1000°C annealing.