The Influences of Oxygen Incorporation on the Defect Trap States of a-IGZO Thin-Film Transistors

Abstract

Thin-film transistors (TFTs) comprised of amorphous indiumgallium-zinc-oxide (a-IGZO) as the active channel layers were prepared by sputtering process at various Ar/O 2 gas flow ratios and their electrical properties were investigated. Device characterizations indicated that the TFT sample prepared at the condition of Ar/O 2 ratio = 20:0.6 exhibits the best performance with field-effect mobility (μ FE) = 5.2 cm 2 ⋅V −1 ⋅sec −1 , threshold voltage (V th) = 0.7 V, subthreshold gate swing (S.S.) = 0.9 V⋅decade −1 and on/off ratio = 5×10 6. Such a sample also exhibited the lowest interface trap density (D it = 2.8×10 10 eV −1 ⋅cm −2) and the highest capacitance density (334 nF⋅cm −2) as revealed by capacitance-voltage (C-V) analysis and the lowest leakage current density of 25 nA/cm 2 at 10 MV/cm (in case of positive bias on top electrode) as revealed by current-voltage (I-V) measurement.

Highly Bendable In-Ga-ZnO Thin Film Transistors by Using a Thermally Stable Organic Dielectric Layer

“…Lo et al . demonstrated the effect of the gas (Ar:O 2 ) flow ratio on the trap density at the interface and reported a lower trap density for lower oxygen flow rates37. The TFT fabricated at OPP1 exhibited a hysteresis value of ~4 V at 30 V drain bias (SI, S5) along with the best device performance, including a mobility of 15.64 cm 2 /Vs, a threshold voltage of 6.5 V, and a I on/off of 4.5 × 10 5 .…”

Facile fabrication of high-performance InGaZnO thin film transistor using hydrogen ion irradiation at room temperature

“…Many research groups reported that interface defect density between gate insulator and IGZO, which has an amorphous structure. [12][13][14] One group suggested an experimental method for obtaining D it by metal-insulator-IGZO MIS capacitors. The other groups calculated the D it by SS value obtained TFT.…”