Liquid antimony pentachloride as oxidant for robust oxidative chemical vapor deposition of poly(3,4-ethylenedioxythiophene) films

The oxidative chemical vapor deposition (oCVD) process is investigated to produce poly (3,4-ethylenedioxythiophene) (PEDOT) thin films on 10 cm diameter Si wafers, involving the SbCl5 liquid oxidant. Process/structure/properties correlations are thoroughly studied, including the influence of the SbCl5/EDOT ratio, substrate temperature (T-sub), total pressure and deposition duration, on the thickness, composition, morphology, spatial uniformity of the films, and on their electrical conductivity and optical transmittance. The electrical conductivity of the films increases by decreasing the oxidant/EDOT ratio and by increasing the substrate temperature. Such increase of substrate temperature results in the decrease of the deposited mass and thickness. Films uniformity and electrical conductivity are improved by decreasing the total pressure. Operating at 75 Pa results in films of equal and uniform thickness deposited on substrates located all over the deposition chamber, proving the potential of the PEDOT-SbCl5 oCVD process to be scaled up over larger surfaces. The absence of post deposition liquid rinsing allows developing a full dry process, which is of interest to coat sensitive substrates and can thus be implemented for the processing of devices requiring durable, transparent, conductive PEDOT thin films, in particular in the field of optoelectronics.

Automated summary

By adjusting the SbCl5/EDOT ratio and substrate temperature, the electrical conductivity of PEDOT films can be increased, while decreasing the total pressure improves film uniformity and electrical conductivity.