Low-Temperature Fabrication of Amorphous Zinc-Tin-Oxide Thin Film Transistors with In-Situ Annealing Process

Abstract

This study analyzes the effect of heating during deposition on the electrical and material properties of zinc tin oxide (ZTO) thin film transistors (TFTs). Instead of post-deposition annealing (PDA) at more than 300 • C, the ZTO-TFTs were fabricated by heating the substrate to 150∼200 • C with 0∼20% of oxygen in chamber and low temperature PDA in air atmosphere. As a result, it was possible to fabricate devices that show similar electrical characteristics with mobilities of 5.8-27.1 cm 2 V-1 s-1 , I on /I off of 10 8 , and subthreshold swing of 0.15∼1.7 V dec −1 , while lowering the process temperature by more than 100 • C. We also proceeded to fabricate a device on polymer substrate, which is the ultimate goal of lowering the process temperature. ZTO-TFTs possessing transparency and flexibility were successfully fabricated on 125 μm polyethylene naphthalate (PEN) substrates. They showed electrical properties with a mobility of 1.7 cm 2 V-1 s-1 , I on /I off of 10 8 , and subthreshold swing of 0.39 V dec −1 .

Plasma Enhanced Atomic Layer Deposition of Silicon Nitride for Two Different Aminosilane Precursors Using Very High Frequency (162 MHz) Plasma Source

“…Silicon nitride (SiN x ) thin films are still actively investigated for next-generation semiconductor devices as a gate spacer for memory and logic devices and charge storage layer for nonvolatile memory devices. − The conventional deposition of SiN x thin films such as in low-pressure chemical vapor deposition (LPCVD) requires high temperatures (>600 °C), which is not compatible with the deposition of the metal layer of the semiconductor devices. − Moreover, applications such as amorphous oxide semiconductor (AOS) low-temperature (<400 °C) SiN x deposition as a phase transition can occur at higher temperatures (400–500 °C). − Besides the issues involved in lowering the process temperature, there are other process related requirements such as accurate thickness control, high conformality, and stability during the integration of semiconductor devices. − Therefore, the plasma-enhanced atomic layer deposition (PEALD) process that could lower the process temperature while maintaining the advantages of ALD is a promising technology among various SiN x thin film deposition methods. − …”