Gallium–Phosphide Films Deposited by Sputtering

Gallium–phosphide films have been deposited by sputtering from a bulk p-type GaP target using radio frequency (rf), dc, and combined rf-dc glow discharges in argon at $30×10−3 Torr$⁠. Any one of these methods yielded p-type semiconductor films of GaP at rates of up to 1100 Å/min. The films, deposited on glass substrates, were either amorphous or polycrystalline; at a given substrate temperature the deposition rate required for the polycrystalline film was higher than for the amorphous one. Deposition at increasingly high substrate temperatures or annealing after the deposition at ∼700 °C resulted in improvement of the optical properties, which is interpreted as being due to the removal of defects.