Reduction of off-state leakage current in Schottky barrier thin-film transistors (SBTFT) by a field-induced drain

Detailed conduction mechanisms in a conventional Schottky barrier thin-film transistor (SBTFT) and a recently proposed novel SBTFT with field-induced drain (FID) extension have been studied. The new SBTFT device with FID extension shows excellent ambipolar performance with effective suppression of gate-induced drain leakage (GIDL)-like off-state leakage that plagues conventional SBTFT devices. By characterizing the activation energy of the conduction process in the off-state for conventional SBTFT devices, it is suggested that field emission of carriers from the drain junction is the major conduction mechanism. While for the FID SBTFT devices, owing to the effect of Fermi level pinning in the FID region, thermionic emission rather than field emission becomes the dominant conduction mechanism, resulting in the effective suppression of the undesirable GIDL-like leakage current.