Excimer-Laser-Induced Chemical Vapor Deposition of Hydrogenated Amorphous Silicon

Hydrogenated amorphous silicon (a-Si:H) films were rapidly deposited (55 Å/s) by the laser-induced chemical vapor deposition (LCVD) technique. An ultraviolet pulsed ArF excimer laser was used for excitation of disilane gas. The films were characterized by photo and dark conductivity, optical bandgap, and infrared (IR) absorption spectroscopy measurements. The IR spectra showed that the films prepared at a lower substrate temperature had incorporated more hydrogen. A photo-conductivity of 2×10-4 Scm-1, a dark conductivity of 2×10-9 Scm-1, and an optical bandgap of 1.75 eV were obtained at a deposition rate of 1 Å/s. Spontaneous emission from silicon atoms, hydrogen atoms, and silicon-monohydride molecules, was observed by optical emission spectroscopy (OES).