Investigations on the effects of electrode materials on the device characteristics of ferroelectric memory thin film transistors fabricated on flexible substrates. (8th February 2018)

• Record Type: Journal Article
• Authors: Yang, Ji-Hee; Yun, Da-Jeong; Seo, Gi-Ho; Kim, Seong-Min; Yoon, Myung-Han; Yoon, Sung-Min
• Is Part Of: Japanese journal of applied physics. Volume 57:Number 3(2018)Supplement 1
• Publication Date: 2018-02-08
• Subjects: Physics -- Periodicals; 621.05
• DOI: 10.7567/JJAP.57.03DB02
• Languages: English
• ISSNs: 0021-4922

Abstract

Abstract: For flexible memory device applications, we propose memory thin-film transistors using an organic ferroelectric poly(vinylidene fluoride–trifluoroethylene) [P(VDF–TrFE)] gate insulator and an amorphous In–Ga–Zn–O (a-IGZO) active channel. The effects of electrode materials and their deposition methods on the characteristics of memory devices exploiting the ferroelectric field effect were investigated for the proposed ferroelectric memory thin-film transistors (Fe-MTFTs) at flat and bending states. It was found that the plasma-induced sputtering deposition and mechanical brittleness of the indium–tin oxide (ITO) markedly degraded the ferroelectric-field-effect-driven memory window and bending characteristics of the Fe-MTFTs. The replacement of ITO electrodes with metal aluminum (Al) electrodes prepared by plasma-free thermal evaporation greatly enhanced the memory device characteristics even under bending conditions owing to their mechanical ductility. Furthermore, poly(3, 4-ethylenedioxythiophene)–poly(styrene sulfonate) (PEDOT:PSS) was introduced to achieve robust bending performance under extreme mechanical stress. The Fe-MTFTs using PEDOT:PSS source/drain electrodes were successfully fabricated and showed the potential for use as flexible memory devices. The suitable choice of electrode materials employed for the Fe-MTFTs is concluded to be one of the most important control parameters for highly functional flexible Fe-MTFTs.