Control of radical species in microwave plasma chemical vapor deposition

The spatial distributions of electron temperature and density in pure Ar plasma in a double-tubed coaxial-line type microwave plasma chemical vapor deposition (CVD) system were measured using the probe method. It was found that the electron temperature and electron density dropped sharply in an area 4 cm from the edge of the discharge tube and they decreased slowly in an area farther away from the forementioned area. SiH₄ gas was dissociated in Ar plasma, and the electron temperature and density of the plasma were varied by changing the location of the SiH₄ gas inlet. As a result, it was found that the fragmentation pattern of radical species could be varied by changing the location of the SiH₄ gas inlet.