A write-once-read-many-times memory based on a sol-gel derived copper oxide semiconductor

Abstract

In this paper, we demonstrate the write-once-read-many-times (WORM) characteristics of the Al/CuxO/n+-Si memory device. The CuxO oxide semiconductor used as the resistive switching layer was fabricated using a sol-gel process. The device is initially in a high-resistance state (HRS) with a resistance of ∼107 Ω. The writing process only occurs in the positive voltage region regardless of the initial voltage sweep direction, followed by a resistance switching to a value of ∼103 Ω. Then the memory remains in the low-resistance state (LRS) in the following voltage cycles. The read-endurance and read-disturb tests were performed to the memory device. The memory window is 104 for 104 pulse cycles. The sol-gel CuxO thin film is verified and analyzed by ultraviolet–visible (UV–vis) spectroscopy and X-ray photoelectron spectroscopy (XPS). The resistive switching and carrier transport mechanisms are also investigated.