Defect generation in a data-storage layer by strong ion bombardment for multilevel non-volatile memory applications

Abstract

Neuromorphic devices and systems have been widely studied for future computing platforms. For an accurate neural network, each memory cell in the system requires multilevel data to support sufficient weight levels. However, conventional memory devices have limitations in increasing the data levels while maintaining low power consumption. In this study, we demonstrate that a strong ion bombardment process can be a viable solution for multilevel memory. During sputter deposition of a data-storage layer in charge trap flash, a substrate bias increases the total trap density by 64%, which significantly enhances the memory window and data levels. From secondary ion mass spectrometry and X-ray photoelectron spectroscopy, we reveal that the origin of the increase in trap states is the ejection of O atoms by the bombardment process. The present work provides a novel strategy to increase the data levels of a memory device, and thus, paves the way for reliable neuromorphic hardware system.