Influence of active layer thickness on performance and reliability of InSnZnO thin-film transistors

The bottom-gate amorphous InSnZnO (a-ITZO) thin-film-transistors (TFTs) with various channel thicknesses were fabricated to investigate the effect of an active layer thickness on performance and reliability of the TFTs. The a-ITZO TFTs showed the excellent electrical performance such as field effect mobility (21.7-51.7 cm
²
v
^-1
s
^-1
) and subthreshold swing (0.19-0.35 V/decade). It was found that the area density of traps decreased as the channel thickness increased. After applying a positive gate bias stress, the threshold voltage shift decreased when the channel layer thickness increased. In contrast, after applying a negative gate bias stress little thickness dependence of the threshold voltage shift, was observed.