Features of embedding non-volatile memory elements in CMOS technology

This review article provides a comprehensive analysis of the structural and technological aspects of integrating various types of non-volatile memory into CMOS VLSI technology. It examines the fundamental operating principles and structural characteristics of the most widely used non-volatile memory architectures, including FLASH, EEPROM, SONOS, FeRAM, MRAM, and resistive memory (ReRAM, PCM). The paper also presents a detailed breakdown of the submicron CMOS VLSI fabrication process, distinguishing between the FEOL and BEOL stages. Based on an extensive review of current scientific and technical literature, the study identifies key challenges and technological constraints in embedding each type of memory, such as thermal incompatibility, material limitations, the need for additional photolithographic steps, and modifications to existing fabrication processes. The article systematizes modern strategies for overcoming these barriers, including low-temperature deposition techniques, optimized thermal processing, barrier layer implementation, and specialized architectural solutions. These findings contribute to the development of new fabrication approaches and the refinement of existing processes for integrating non-volatile memory into advanced semiconductor devices.