Hydrogen plasma enhanced crystallization of hydrogenated amorphous silicon films

We report that a room temperature hydrogen plasma exposure in a parallel plate diode type reactive ion etcher can reduce the time required for the subsequent thermal crystallization of amorphous silicon time by a factor of five. Exposure to hydrogen plasma reduces the incubation time, while the rate of crystallization itself is not greatly affected. This plasma enhanced crystallization can be spatially controlled by masking with patterned oxide, so that both amorphous and polycrystalline areas can be realized simultaneously at desired locations on a single substrate. The enhancement of crystallization rate is probably due to the creation of seed nuclei at the surface. The films have been characterized by UV reflectance, x-ray diffraction, plan view transmission electron microscopy, Fourier transform infrared absorption, secondary ion mass spectroscopy, and four-point probe measurement of electrical conductivity. (C) 1999 American Institute of Physics. [S0021-8979(99)09503-1].