Effects of Capping Layers with Different Metals on Electrical Performance and Stability of p-Channel SnO Thin-Film Transistors.

Min-Gyu Shin,Hyun-Seok Cha,Dae-Hwan Kim,Hyuck-In Kwon,Kang-Hwan Bae,Hwan-Seok Jeong

doi:10.3390/mi11100917

Min-Gyu Shin, Hyun-Seok Cha + Show 4 more

Open Access

https://doi.org/10.3390/mi11100917

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Journal: Micromachines	Publication Date: Sep 30, 2020
Citations: 8	License type: CC BY 4.0

Affiliation: Chung-Ang University

Abstract

In this study, the effects of capping layers with different metals on the electrical performance and stability of p-channel SnO thin-film transistors (TFTs) were examined. Ni- or Pt-capped SnO TFTs exhibit a higher field-effect mobility (μFE), a lower subthreshold swing (SS), a positively shifted threshold voltage (VTH), and an improved negative-gate-bias-stress (NGBS) stability, as compared to pristine TFTs. In contrast, Al-capped SnO TFTs exhibit a lower μFE, higher SS, negatively shifted VTH, and degraded NGBS stability, as compared to pristine TFTs. No significant difference was observed between the electrical performance of the Cr-capped SnO TFT and that of the pristine SnO TFT. The obtained results were primarily explained based on the change in the back-channel potential of the SnO TFT that was caused by the difference in work functions between the SnO and various metals. This study shows that capping layers with different metals can be practically employed to modulate the electrical characteristics of p-channel SnO TFTs.

Highlights

Since the first report on indium-gallium-zinc oxide thin-film transistors (TFTs) by Nomura et al in 2004, oxide semiconductor TFTs have drawn significant attention owing to their high electrical performance, low fabrication temperature, and superior large area uniformity [1,2,3,4,5,6,7,8,9,10]
We demonstrated that the formation of a Ni capping layer can increase the field-effect mobility of p-channel SnO TFTs
We compared the electrical performance and stability of p-channel SnO TFTs consisting of capping layers with different metals (Al, Ni, Pt, and Cr) to thoroughly understand the effects of a metal capping layer on p-channel SnO TFTs

Summary

Introduction

Since the first report on indium-gallium-zinc oxide thin-film transistors (TFTs) by Nomura et al in 2004, oxide semiconductor TFTs have drawn significant attention owing to their high electrical performance, low fabrication temperature, and superior large area uniformity [1,2,3,4,5,6,7,8,9,10]. No significant difference was observed between the electrical properties of the Cr-capped SnO TFT (μFE = 1.8 cm2/V·s, SS = 3.9 V/decade, and VTH = 4.5 V) and the pristine SnO TFT.

Results

Conclusion