Development of organic flash memory devices and application for next-generation processing device with heterojunction transistors

Abstract

As enter of advanced information society, there is a growing demand for wearable devices. Consequently, the development and industrialization of various electronic devices using organic materials have been taking place. However, information processing still predominantly relies on inorganic-based components such as CPUs and GPUs. Therefore, there is a significant interest in flexible flash memory for wearable devices. Organic-based flash memories are gaining attention as essential devices of future electronic components due to their mechanical flexibility and lightweight characteristics. In particular, organic flash memory, based on organic thin-film transistor structures, can exhibit the same effect as applying voltage when introducing an electron storage layer, enabling memory operation. However, previous flexible flash memory faced issues with high operating voltages and reduced stability, necessitating the introduction of materials with excellent insulation properties, even in thin film thicknesses. This paper aims to develop low-voltage, highly stable operable organic memory and further enhance the utility for processing of these memory components. The insulating material was developed through a process of initiated chemical vapor deposition (iCVD). iCVD process enables the deposition of high-purity polymer films with excellent uniformity, allowing for polymerization through uniform mixing in the atmosphere without phase separation. By applying materials with suitable insulation properties and appropriate dielectric constant characteristics to the memory components, we have developed organic flash memory that operates at low voltages while demonstrating high stability. Furthermore, we propose a novel application by connecting or introducing memory structures into heterojunction semiconductors, which combine p-type and n-type semiconductors. Through the connection of heterojunction transistors and organic memory, we implemented a ternary operation circuit with adjustable electrical properties. Additionally, by directly combining memory structures with heterojunction transistor, we developed a Gaussian-shaped, adjustable-output memory, enabling nonlinear computations and creating intelligent computational devices. In conclusion, this research has presented the development of high-performance organic flash memory and demonstrated new applications as processing unit.