Abstract
How to create a multi-bit non-volatile memory device is a crucial topic. Non-volatile memory (NVM) is getting more important in the integrated circuit industry. The ability to retain data when power is turned off becomes a huge advantage when creating applications for computer and communication fields. As technology has become more advanced and the demand for NVM has grown significantly. The need to store huge amounts of information at high-densities is increasing, this has led to a new-generation information storage technologies. Sb2S3 is a phase change material that can behave as resistive memory (ReRAM) Ionic diffusion through Sb2S3 occurs when an electric voltage is applied and when it is heated above its crystallisation temperature. It can switch from amorphous state to crystalline state. The electrical switching characteristics of Sb2S3-based memory devices are studied herein. To enable the ionic diffusion, an asymmetric device is fabricated with Ag and Graphene electrodes. When an electrical potential difference is applied to the electrodes, Ag charged ions respond to it and diffuse through the Sb2S3. The bipolar switching time for the device is around 50 ms when 0.20 V is applied. The device resistance changes by eight orders of magnitude and can endure more than 10,000 write-erase cycles. Here I hypothesise that combining this effect with phase change could enable a 2-bit memory in a single cell. Therefore, a hybrid phase change and resistive memory concept are useful for high-density data storage applications. I also believe that these multi-bit non-volatile memory devices will also be useful in solid-state artificial neural networks.