Comparative study of a‐IGZO TFTs with direct current and radio frequency sputtered channel layers

E-ISSN： 1938-3657|23|7|306-312

ISSN： 1071-0922

Source： JOURNAL OF THE SOCIETY FOR INFORMATION DISPLAY, Vol.23, Iss.7, 2015-07, pp. : 306-312

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Abstract

AbstractIn this work, a comparative study of electrical properties and gate‐bias stress stability between direct current (DC)‐sputtered and radio frequency (RF)‐sputtered amorphous indium–gallium–zinc oxide thin film transistors (a‐IGZO TFTs) is conducted. The RF‐sputtered a‐IGZO TFTs show higher field‐effect mobility and steeper sub‐threshold slope. The DC‐sputtered ones show a better uniformity of threshold voltage, enhanced stability under both positive bias stress and negative bias illumination stress. The X‐ray photoelectron spectroscopy characterization of the a‐IGZO films reveals that the concentration of oxygen vacancies and electron density in the RF‐sputtered a‐IGZO film is higher than that in the DC‐sputtered one, which probably accounts for the differences of electrical properties between the RF‐sputtered and DC‐sputtered a‐IGZO TFTs.