Interpretation of Device Characteristics of Wide-Width InGaZnO Transistors for Gate Driver Circuits

Oxide semiconductor thin-film transistors (TFTs) with various device dimensions are integrated on the same substrate for different purposes and functionality. However, unlike length scalability, the width-dependence of oxide TFTs is seldom reported. Current increase proportional to the channel width and lower threshold voltage (
${V}_{{{th}}}$
) are found in devices with wide channel width. In this study, we investigate InGaZnO TFTs with various widths to examine the width-dependent characteristics via device characterization and simulation. We introduce a random potential distribution (RPD) model to reproduce the observed device characteristics at different dimensions. The RPD model shows that devices with larger channel width and shorter gate length have a high probability to form conductive paths at a lower Fermi level, resulting in a decreased
${V}_{{{th}}}$
agreeing with experimental characteristics.