Effect of ELA on a-IGZO TFT
Effect of Excimer Laser Annealing on the Performance of Amorphous Indium Gallium Zinc Oxide Thin-Film Transistors
This article reports a method for reducing the contact resistance between amorphous-InGaZnO (a-IGZO) channel and source/drain layer via XeCl excimer laser annealing (ELA) and the device performance of a-IGZO thin-film transistors (TFTs) in terms of laser energy density. The source/drain region in the a-IGZO layer was selectively ELA-treated using a mask, and the resistivity dramatically reduced compared to that of the untreated film (from 104 to 10-3 Ω cm). Our TFTs had a field-effect mobility of 21.7 cm2/Vs, an on/off ratio of 1.2 x 108, a threshold voltage of −0.15 V, and a subthreshold swing of 0.26 V/decade.
Table I shows that μFE significantly increased with increasing laser energy density to 130 mJ/cm2. The S value and Ion/off ratio were improved to 0.26 V/decade and 1.2 x 108, respectively, for the devices that were laser-irradiated at 130 mJ/cm2, and VT was shifted to nearly zero 0.15 V, which is desirable for low power consumption AMLCDs and AMOLEDs.