THIN COPPER SULFIDE FILMS PRODUCED BY PLASMA-ENHANCED CHEMICAL-VAPOR-DEPOSITION USING COPPER DIETHYLDITHIOCARBAMATE

Thin Cu2S films were grown by a novel low-pressure (0.2 Pa) plasma-enh anced chemical vapor deposition process using the volatile chelate Cu( II) diethyldithiocarbamate as a metalorganic precursor. The process, a ctivated by a constant-power rf plasma, with helium as a carrier gas, ensures a reduction in substrate temperature to 473-573 K. The grown f ilms were characterized by ellipsometry, IR spectroscopy, scanning ele ctron microscopy, and synchrotron x-ray diffraction. The film thicknes s varies from 200 to 600 nm, and the refractive index from 2.0 to 2.21 , depending on deposition conditions. The resistivity of the films is 5.7 x 10(-2) Ohm cm. The films are transparent in the visible range, w ith a transmittance of about 60% between 600 and 700 nm. The structure of the films depends on that of the substrate: polycrystalline hexago nal + cubic two-phase films were obtained on fused quartz, single-crys tal cubic films on Si(100), and polycrystalline hexagonal films on CdS /Si(100) heterostructures.