Low Voltage a-IGZO Thin Film Transistor Using Tantalum Oxide by Thermal Oxidation

Abstract

Low voltage oxide thin-lm transistors (TFTs) operating below 1.0 V were developed using a high dielectric constant tantalum oxide produced by thermal oxidation. Thermal oxidation was carried out at 400, 500, and 600 °C under an oxygen atmosphere. The tantalum oxide was evaluated by X-ray photoelectron spectroscopy (XPS). XPS con rmed the binding energy of Ta4f, indicating the binding state of tantalum oxide. The bottom gate oxide TFT with the gate insulator of tantalum oxide grown at 500 °C exhibited mobility of 12.61 cm2/V and a threshold voltage of 0.46 V. The transfer characteristics at the drain voltages below 1.0 V show its applicability to low voltage operation below 1 V. The bootstrapped inverter with developed oxide TFTs operated well at the operation voltages of both the 1.0 and 2.0 V.

Modulation of electrical properties of sputtered Ta2O5 films by variation of RF power and substrate temperature

“…The properties of the thin film greatly depend upon the methods of preparation and post-deposition treatments. Though preparation of high-quality Ta 2 O 5 film is a challenging issue, many possible methods are used to fabricate Ta 2 O 5 thin film such as chemical vapor deposition (CVD) technique [27], thermal oxidation [28], e-beam evaporation [29], atomic layer deposition [30], anodization [31], DC sputtering [32], RF sputtering [20] and sol-gel process [33]. Among these techniques, RF reactive magnetron sputtering has many advantages due to its low deposition temperature, non-toxic approach, uniformity, conformal coverage, and high yield [34][35][36].…”