Stabilizing solution-processed metal oxide thin-film transistors via trilayer organic–inorganic hybrid passivation

Xiaozhu Wei,Shohei Kumagai,Jun Takeya,Shun Watanabe,Mari Sasaki

doi:10.1063/5.0038128

Abstract

Solution-processed amorphous metal oxide semiconductors (AOSs) are promising candidates for printed electronics. However, process durability and bias stress instability issues still hinder their practical applications. Here, a poly(methyl methacrylate)/parylene/AlOx hybrid passivation approach was developed for AOS thin-film transistors (TFTs) to overcome these challenges. Notably, AlOx was successfully formed without degrading the AOS TFTs owing to the polymer buffer layers. The hybrid passivation approach ensured the satisfactory stabilization of the TFTs under bias stress owing to the high isolation effect, which could prevent the penetration of environmental molecules. This passivation method can facilitate the application of solution-processed AOSs in integrated circuits.

Highlights

Utilizing printed electronics is a promising way to realize the Internet of Things (IoT) society because of its high throughput
atomic layer deposition (ALD) and parylene-coating processes tend to vary the thin-film transistors (TFTs) properties based on solution-processed amorphous metal oxide semiconductors (AOSs)
The poly(methyl methacrylate) (PMMA)/parylene bilayer structure acted as a strong buffer layer for the TFTs during the ALD of AlOx, whereby evident TFT performance degradation was not observed [Fig. 2(f)]

Summary

INTRODUCTION

Utilizing printed electronics is a promising way to realize the Internet of Things (IoT) society because of its high throughput. TFT performance degradation has been observed after their deposition processes, such as plasma-enhanced chemical vapor deposition (CVD), atomic layer deposition (ALD), and sputtering.[17,21,22] Another encapsulant is insulating polymers, such as CYTOP,[21,23] parylene,[24] and some reactive resins,[25–27] which are compatible with mild processing conditions, and generate inconsiderable process-induced damage. Such polymers exhibit insufficient protection abilities owing to their high gas and water penetration rates compared with their inorganic counterparts.[22]. Scitation.org/journal/adv obtain strong protection without performance degradation With this hybrid structure, a thin PMMA/parylene bilayer acted as a buffer from damage resulting from the ALD process for AlOx, and the resultant AlOx had a strong isolation effect. A poly(methyl methacrylate) (PMMA)/parylene/ AlOx hybrid passivation technique was developed to simultaneously

EXPERIMENT

RESULTS AND DISCUSSION

CONCLUSION