The Effect of Passivation Layers on the Negative Bias Instability of Ga-In-Zn-O Thin Film Transistors under Illumination

Ga-In-Zn-O (GIZO) thin film transistors (TFTs) with disparate passivation structures were fabricated and their stabilities were compared. The devices were subjected to a negative bias stress with simultaneous exposure to visible light. TFT that incorporates a dual passivation composed of a SiO x layer grown at a relatively high temperature with an additional SiN x film deposited shows only -0.8 V V th shift, whereas a -5.7 V shift was observed for a TFT covered by a single SiO 2 film. The device degradation is susceptible to the ability of protecting external moisture, which may adsorb on the surface of the GIZO semiconductor to create donor states therein.

[1]  M. Powell,et al.  Charge trapping instabilities in amorphous silicon‐silicon nitride thin‐film transistors , 1983 .

[2]  V. Walle,et al.  Hydrogen as a cause of doping in zinc oxide , 2000 .

[3]  Barrier Effect of Electron Cyclotron Resonance Sputtered Films Against Water and Hydrogen Molecules Permeation , 2002 .

[4]  H. Ohta,et al.  Room-temperature fabrication of transparent flexible thin-film transistors using amorphous oxide semiconductors , 2004, Nature.

[5]  E. Fortunato,et al.  Fully Transparent ZnO Thin‐Film Transistor Produced at Room Temperature , 2005 .

[6]  T. Kamiya,et al.  42.1: Invited Paper: Improved Amorphous In‐Ga‐Zn‐O TFTs , 2008 .

[7]  Hyun-Joong Chung,et al.  Electronic transport properties of amorphous indium-gallium-zinc oxide semiconductor upon exposure to water , 2008 .

[8]  Sunghoon Song,et al.  Passivation effects on ZnO nanowire field effect transistors under oxygen, ambient, and vacuum environments , 2008 .

[9]  Jang-Yeon Kwon,et al.  The effect of moisture on the photon-enhanced negative bias thermal instability in Ga-In-Zn-O thin film transistors , 2009 .

[10]  M. Nakata,et al.  Comparison of Ultraviolet Photo-Field Effects between Hydrogenated Amorphous Silicon and Amorphous InGaZnO4 Thin-Film Transistors , 2009 .

[11]  Ji Sim Jung,et al.  Threshold Voltage Control of Amorphous Gallium Indium Zinc Oxide TFTs by Suppressing Back-Channel Current , 2009 .

[12]  Jang-Yeon Kwon,et al.  The Impact of Device Configuration on the Photon-Enhanced Negative Bias Thermal Instability of GaInZnO Thin Film Transistors , 2010 .