Ti-doping in Silicon Nitride: Enhanced Charge Trap Characteristics for Flash Memory

Abstract

Advanced materials technologies have been extensively studied to overcome the limitations of conventional charge trap flash (CTF) memory driven by the increasing demand for data storage. This study investigates the impact of titanium (Ti) doping in silicon nitride (SiN_x) on memory performance and explores systematically the CTF memory mechanisms. Our findings reveal a remarkable enhancement in memory performance, with Ti doping expanding the memory window width by over 60% and improving charge retention characteristics by more than 20%. Using techniques such as photoluminescence, Raman spectroscopy, X-ray photoelectron spectroscopy, and reflection electron energy loss spectroscopy, we elucidate the mechanisms behind the enhanced charge trap characteristics and the role of Ti within SiN_x, including the suppression of oxygen-related shallow traps. Notably, Ti-doping is compatible with CMOS fabrication processes, facilitating seamless integration into existing manufacturing protocols. The devices were deposited at room temperature, considerably lower than the formation temperature of conventional flash memory, potentially offering innovative low-temperature processing options in flash memory fabrication.