Copper sulfide films deposited by cylindrical magnetron reactive sputtering

Abstract

Copper sulfide coatings 150 nm thick were deposited by reactive sputtering using a copper cylindrical magnetron sputtering source in an Ar–H2S atmosphere at constant discharge current and varies H2S injection rates. Borosilicate plate-substrates were maintained at temperatures of 130° and 35°C, which are above and below transition temperatures for the CuxS phases of interest. Above a critical injection rate resistivity data indicate two types of materials: a high-resistivity type (∠100 Ω cm) often exhibiting Cu-rich nodules, and a low-resistivity type (∠0.01 Ω cm). The types are generally associated with the high and low substrate temperatures respectively. Hall mobilities were in the 1–6 cm2/V s range for both materials. Optical absorption, resistivity-versus-temperature, and x-ray diffraction measurements indicate that the high resistivity material consists largely of near-stoichiometric chalcocite and that the low resistivity material is a mixture of chalcocite and djurleite.