P-type CuxS thin films: Integration in a thin film transistor structure

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Abstract

CuxS thin films, 80 nm thick, are deposited by vacuum thermal evaporation of sulfur-rich powder mixture,Cu2S:S (50:50 wt.%) with no intentional heating of the substrate. The process of deposition occurs at verylow deposition rates (0.1-0.3 nm/s) to avoid the formation of Cu or S-rich films. The evolution of CuxS films surface properties (morphology/roughness) under post deposition mild annealing in air at 270 °Cand their integration in a thin film transistor (TFT) are the main objectives of this study. Accordingly, Scan-ning Electron Microscopy studies show CuxS films with different surface morphologies, depending on thepost deposition annealing conditions. For the shortest annealing time, the CuxS films look to be constructedof grains with large dimension at the surface (approximately 100 nm) and consequently, irregular shape. Forthe longest annealing time, films with a fine-grained surface are found, with some randomly distributed largeparticles bound to this fine-grained surface. Atomic Force Microscopy results indicate an increase of theroot-mean-square roughness of CuxS surface with annealing time, from 13.6 up to 37.4 nm, for 255 and 345 s, respectively. The preliminary integration of CuxS films in a TFT bottom-gate type structure allowedthe study of the feasibility and compatibility of this material with the remaining stages of a TFT fabricationas well as the determination of the p-type characteristic of the CuxS material.
Original languageUnknown
Pages (from-to)3-6
JournalThin Solid Films
Volume543
Issue numberNA
DOIs
Publication statusPublished - 1 Jan 2013

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