4:00 PM - 4:50 PM
▲ [19p-P04-1] Effect of Gate Voltage on the Thermoelectric Properties of an InGaZnO/SiO2 Standard Thin Film Transistor
Keywords:thermoelectric TFT, InGaZnO thermoelectric, oxide TFT
Indium gallium zinc oxide (InGaZnO) is commonly used as a channel layer thin film transistors (TFT) owing to its low temperature processability, superior mobility, and low leakage current. However, its thermoelectric (TE) properties are relatively less-explored. In this study, the TE performance of a typical InGaZnO TFT with SiO2 gate insulator is investigated. Bottom-gate top-contact TE-TFTs were fabricated on p-type Si gate electrode with 85 nm of thermally oxidized SiO2 layer as the gate insulator. The InGaZnO channel (70 nm) was deposited via RF magnetron sputtering at room temperature. Next, a metal thin film layer (80 nm Ti/20 nm Au) was deposited via electron beam evaporation. The channel islands, as well as the source and drain electrodes were patterned by standard photolithography. Finally, the fabricated devices were post-annealed at 300°C for 2h under air. To measure the Seebeck coefficient (S), the method by Liang, et. al was adopted. The InGaZnO TE-TFT exhibit proper switching, with a μ = 10.4 cmV-1S-1. This suggests typical transistor behavior, even at a low VD of 100 μV, where the Seebeck voltage is expected to range. Similarly, the PF exhibits a switching behavior under positive VG, with a maximum of ~0.1 mW/mK2 at VG = 40 V. This superior PF can mostly be attributed to the σ increasing by two orders of magnitude, while maintaining a decrease in S to only ~35%. This suggests a possible suppression of the coupling reaction of S and σ, owing to the electron confinement at the extremely narrow accumulation layer formed at the InGaZnO/SiO2 interface.