A solution-processed quaternary oxide system obtained at low-temperature using a vertical diffusion technique

Seokhyun Yoon,Hyun Jae Kim,Young Jun Tak,Si Joon Kim

doi:10.1038/srep43216

Abstract

We report a method for fabricating solution-processed quaternary In-Ga-Zn-O (IGZO) thin-film transistors (TFTs) at low annealing temperatures using a vertical diffusion technique (VDT). The VDT is a deposition process for spin-coating binary and ternary oxide layers consecutively and annealing at once. With the VDT, uniform and dense quaternary oxide layers were fabricated at lower temperatures (280 °C). Compared to conventional IGZO and ternary In-Zn-O (IZO) thin films, VDT IGZO thin film had higher density of the metal-oxide bonds and lower density of the oxygen vacancies. The field-effect mobility of VDT IGZO TFT increased three times with an improved stability under positive bias stress than IZO TFT due to the reduction in oxygen vacancies. Therefore, the VDT process is a simple method that reduces the processing temperature without any additional treatment for quaternary oxide semiconductors with uniform layers.

Highlights

We report a method for fabricating solution-processed quaternary In-Ga-Zn-O (IGZO) thin-film transistors (TFTs) at low annealing temperatures using a vertical diffusion technique (VDT)
No matrix effects were observed in the VDT IGZO layer, which means that www.nature.com/scientificreports/ Figure 1
We suggest a strategy to reduce the processing temperature for IGZO TFTs using vertical diffusion

Summary

Introduction

We report a method for fabricating solution-processed quaternary In-Ga-Zn-O (IGZO) thin-film transistors (TFTs) at low annealing temperatures using a vertical diffusion technique (VDT). The VDT process is a simple method that reduces the processing temperature without any additional treatment for quaternary oxide semiconductors with uniform layers. At higher processing temperatures, it can be difficult to produce flexible devices because the maximum processing temperature of flexible substrates is below 300 °C To resolve this issue, many researchers have focused on lowering the processing temperature while maintaining high electrical performance. We introduce a simple method to reduce the processing temperature for a quaternary oxide: the vertical diffusion technique (VDT). With the VDT, uniform IGZO TFTs were fabricated with lower processing temperatures and superior electrical performance, without any additional treatment. This approach is expected to be useful in the fabrication of flexible oxide TFTs due to lower fabrication cost and simple process compared to aforementioned methods

Methods

Results

Conclusion