Performance Enhancement of Transparent Amorphous IGZO Thin-Film Transistor Realized by Sputtered Amorphous AlOx Passivation Layer

Abstract

We report a high-mobility transparent Indium-Gallium-Zinc-Oxide (IGZO) thin-film transistor (TFT) with sputtered AlOx passivation layer. The interfacial region between the IGZO layer and the AlOx layer played a crucial role in improving the field-effect mobility (the maximum field-effect mobility increased from 6.292 cm2 Vs−1 for the TFT without the AlOx layer to 69.01 cm2 Vs−1 for the TFT with the passivation layer) and the on/off current ratio (from ∼107 without the layer to ∼108 with the layer). The driving current of IGZO TFT was also significantly enhanced. The formation of the interfacial layer has been investigated and verified. The ion bombardment during the AlOx deposition broke the In-O bond in IGZO, generating oxygen ions (O2−). The segregation of the O2− was facilitated by the sputtered amorphous AlOx. A metallic In-rich layer with high oxygen vacancy concentration was formed at the interface, leading to an increase in the carrier concentration in the interfacial layer. Besides the electrical performance, the reliability tests, including long-term exposure in the ambient environment and positive bias illumination stress (PBIS), showed improved results as well.

Performance improvement of a sol–gel ZTO-based TFT due to an interfacial SnOxdopant layer

“…An increased electron concentration near the contact regions is helpful for preventing current crowding. 28,68,69 The current crowding effect indicates that the transistor current in the linear region, low drain bias region, is insensitive to the applied gate bias. In I DS – V DS output characteristics, the phenomenon that I DS – V DS curves crowd together will be observed.…”

Passivated indium oxide thin-film transistors with high field-effect mobility (128.3 cm2 V−1 s−1) and low thermal budget (200 °C)

“…This mobility enhancement in OSs can be linked to the reduction of defect states within the channel and the alterations in free carrier concentration [13,[25][26][27]. In this regard, the increased µ FE and negative shift in V TH with the sputtered Al 2 O 3 PVL indicate an increment in carrier concentration in In 2 O 3 channels, attributed to ion bombardment effect [13,28]. When Al 2 O 3 PVL is sputtered onto the In-based OS channel, oxidation/reduction reactions occur at the channel and PVL interface.…”

(Digital Presentation) Effect of Active Layer Thickness on Organic Thin-Film Transistors

“…To increase performance, the influence of organic semiconductor thickness on the charge transport in bottom gate and top contact OFET architectures was studied and analyzed (10)(11)(12). Two-dimensional numerical simulations were performed to analyze the physical parameters of the devices, including electric potential profile, carrier distribution density throughout the channel and active layer, and current-voltage characteristics, as a function of the active layer (13)(14)(15)(16).…”