J. Phys. IV France 11 (2001) Pr3-1147-Pr3-1152
Comparative study of atomic layer deposition and low-pressure MOCVD of copper sulfide thin filmsB. Meester, L. Reijnen, A. Goossens and J. Schoonman
Laboratory for Inorganic Chemistry, Delft University of Technology, Julianalaan 136, 2628 Delft, The Netherlands
Thin films of copper sulfide (CuxS) have been prepared on fluor-doped tin dioxide (SnO2 : F) coated glass and on uncoated glass by atomic layer deposition (ALD) and low-pressure chemical vapor deposition (LPCVD). In both cases, copper(II) bis-tetramethylheptanedionate (Cu(thd)2) and H2S are used. CuxS films form between 125 and 300 °C with ALD and between 127 and 505 °C with LPCVD. Deposition rates are obtained between 1 and 109 Å/min by LPCVD and between 0.15 and 0.40 Å/cycle by ALD. Self-limited grow by ALD is achieved up to 250 °C at 2 mbar. It is found that in both processes the temperature determines the crystalline phase of the films. CuS is obtained at low deposition temperatures when using either ALD or LPCVD. A phase transition occurs at 175 °C from pure CuS into pure Cu9S5 with ALD. In the LPCVD process the phase composition of the films starts to change at 230 °C from pure CuS into a mixture of CuS and Cu9S5. Pure Cu9S5 is obtained between 285 and 315 °C. The morphology of LPCVD films are fine-structured with an average grain size of ˜100 nm for films of 500 nm, while 40 nm thinn ALD films consist of grains with an average grain size of ˜100 nm grown in columns perpendicular to the surface.
© EDP Sciences 2001