Investigation of Electrical Characteristics in Low-Temperature Polycrystalline Silicon Thin-Film Transistors Fabricated at Low-Temperature Process

Abstract

In this work, the electrical characteristics of the low-temperature polysilicon thin-film transistors (LTPS TFTs) fabricated at low-temperature process were investigated. To improve the process of AMOLED displays, a lower fabrication temperature is necessary to adopt and investigate since a lower fabrication temperature is suitable for flexible electronics. In general, the fabrication temperature of LTPS TFTs is about $400 ^{\circ}\mathrm{C}$. Therefore, to clarify the impact of lower fabrication temperature, $400 ^{\circ}\mathrm{C}$, $370 ^{\circ}\mathrm{C}$, and $350 ^{\circ}\mathrm{C}$ are chosen as the maximum processing temperature during device fabrication for three TFT samples, respectively. It is found that the lower fabrication temperature device has lower on-current and higher on-resistance. However, a lower off-state leakage current is observed while the process temperature is declining due to trap-assisted thermal field emission. Silvaco TCAD simulation is discussed to support our findings.