Influence of electrode metallization on thin-film transistor performance

The analysis of contact resistance in bottom-gate top-contact thin-film transistors (TFTs) based on nanoparticulate ZnO and a high-k nanocomposite as semiconductor and gate dielectric, respectively, shows that nickel can be used as an alternative to aluminum contacts. Furthermore, an analysis of the morphology of the gate structures and the influence of the work function of the gate metal on the transistor properties is carried out. For this purpose, gate electrodes were made of aluminum (4.28 eV) and gold (5.1 eV). It can be demonstrated that increasing the work function influences the flat-band voltage and thus the turn-on voltage. This effect can also be observed in bottom-gate bottom-contact devices with self-aligned drain/source electrodes.