Construction of WORM-type polyimide memory materials with low threshold voltage by introducing triazole units and conjugated pendant groups

Abstract

Two novel polyimides (PIs) containing triazole unit (TZPEDA-6FDA and TZBPDA-6FDA) are prepared for WORM-type memory devices. The PI-based WORM-type memory devices exhibit low threshold voltage at −2.3 V and −2.6 V, and high ON/OFF current ratio of 105. The triazole units serve as the charge traps and endow the PIs with large dipole moment and WORM-type memory behavior. The phenyl and biphenyl pendant groups are separately introduced into TZPEDA-6FDA and TZBPDA-6FDA to expend the conjugate structure of the donor unit and optimize the electrostatic surface potential distribution of the PIs, which are beneficial for improving the charge-carrier migration and reducing the threshold voltage. The WORM-type memory behavior is governed by the combination of Ohmic, trap-limited space charge limited conduction and charge trapping. The two PI-based memory devices have low power consumption and high operation stability, which are important for the production of high-performance programmable permanent WORM-type memory devices.