NANOPOWDER OF SILICON-NITRIDE PRODUCED IN RADIO-FREQUENCY MODULATED GLOW-DISCHARGES FROM SIH4 AND NH3

Square-wave modulated radio frequency (RF) plasmas have been shown to be a suitable source of nanometric size powder with high purity and co ntrollable nanostructure. This paper reports the production of SIN nan opowder at room temperature and low pressure by RF glow discharge deco mposition of SiH4 and NH3 gases. The RF power was modulated at 0.5 Hz with a duty cycle of 20% in order to control the size of the expelled particles. A study of the particle formation process using in-situ mon itoring of the RF dissipated power is presented. Transmission electron microscopy showed a narrow size distribution of spherical particles f rom 25 to 45 nm and their electron diffraction provided evidence of a short range order in Si or SiN units depending on the precursor gas mi xture. Analysis by Fourier transform infrared spectroscopy revealed th e presence of SiN, NH and SiH bonds and the elemental analysis of the powder determined its chemical composition. (C) 1998 Elsevier Science S.A.