Width-Dependent Self-Heating Properties in Self-Aligned Top-Gate InGaZnO Thin-Film Transistors

As the display industry trends towards higher pixel densities, managing heating and temperature variations within panels becomes increasingly crucial. In this context, our study explores the width-dependent self-heating effects in self-aligned top-gate indium-gallium-zinc oxide (InGaZnO) thin-film transistors (TFTs). By varying the channel width from 21 µm to 105 µm, we systematically analyze the self-heating properties of these transistors under different operational conditions.<br/>Utilizing infrared thermal microscopy and electrical characterization, we detect significant variations in self-heating across different channel widths. Our findings indicate that wider channels experience higher temperature increases at the same input power density (also known as thermal resistance, <i>R</i>_th [m²K/W]), which correlates with increased electrical stress and potential reliability concerns. This result can be better understood by observing the width-normalized <i>I</i>_ds plot. Theoretically, width-normalized <i>I</i>_ds should show no width dependence, but there is a width dependence in the real device. We observed that as the channel width decreases, the influence of edge effects increases, whereas as the channel width increases, the impact of self-heating becomes more pronounced.<br/>Additionally, we examine the impact of self-heating from a single device to the array platform, incorporating thermal resistance values and numerical heat transfer simulations. The results underscore the pivotal role of device geometry in thermal management and performance in TFTs, providing key insights for designing more reliable and efficient electronic devices based on InGaZnO.<br/>This research offers a foundational understanding of self-heating phenomena in TFTs, which is critical for optimizing device architecture and enhancing the performance of next-generation flexible electronics