Di Geng

 TFTs for Display

Key Laboratory of Microelectronics Devices and Integrated Technology, Institute of Microelectronics of the Chinese Academy of Sciences, Beijing, China

Email: digeng@ime.ac.cn

Biography

His current research interests include fabrication and design of high performance Oxide TFT and circuits for flexible display application and beyond.

Abstract for Presentation

High Performance Sub-50nm Channel Length Vertical IGZO TFTs for Active Matrix Application

Oxide semiconductor-based Thin-Film-Transistors (TFTs) such as IGZO-TFTs have been widely investigated in the past double decades due to the advantages of high mobility (>10 cm2/Vs), good uniformity and low process temperature (<400℃) [1-2]. These features enable the application of IGZO TFTs in high performance display panels, such as active-matrix organic light emitting diode (AMOLED). With the development of virtual reality, the high-resolution displays have attracted considerable attention. For the high-resolution display, the pixel area should be reduced by scaling down the channel length to sub-micron region or developing new structure. From the transistor point of view, vertical-channel structure enables a higher density owing to its smaller footprint compared to the planar structure [3-4].

In this work, we propose a novel vertical channel-all-around structure where the gate electrode is surrounded by a gate insulator and an IGZO channel, and its source/drain electrodes are vertically separated by an insulator layer, forming a metal/insulator/metal (MIM) structure. The channel and gate stack is deposited by Plasma-Enhanced Atomic Layer Deposition (PEALD). The impacts of IGZO cycle ratio and plasma power on the device electrical performance are studied. An optimized 50nm-channel-length vertical IGZO FET achieved Ion >30µA/µm and Ioff below 1.8×10-17µA/µm at VDS = 1V.

References

[1] T. Kamiya, et al., “Material characteristics and applications of transparent amorphous oxide semiconductors,” NPG Asia Mater. 2(1) pp. 15-22 (2010).

[2] Nomura, K., et al. "Room-temperature fabrication of transparent flexible thin-film transistors using amorphous oxide semiconductors. " Nature 432.7016(2004):488-492.

[3] Jong-Beom, et al. "Oxide Vertical TFTs for the Application to the Ultra High Resolution Display." SID International Symposium: Digest of Technology Papers 47.2(2016):820-822.

[4] Yeo-Myeong, et al. "Improvement in Device Performance of Vertical Thin-Film Transistors Using Atomic Layer Deposited IGZO Channel and Polyimide Spacer." IEEE Electron Device Letters 38.10(2017):1387-1389.