Electrical Characteristics of Magnesium Doped a-IGZO RRAM: Chemical Vapor Deposition using Enhanced Atmospheric Pressure-Plasma

Abstract

Since the first floating gate memory was introduced in 1968, Non-Volatile Memory (NVM) has been widely investigated and developed for permanent data storage. The progress of metal oxide semiconductor field-effect transistor (MOSFET) technology even makes the memory scalable. The scale-down of the memories faces other issues. The thinner oxide layer induces a higher leakage current and worse electrical characteristics. There are promising NVMs such as ferroelectric (FeRAM), phase-change (PCRAM), magneto-resistive (MRAM), and resistive (RRAM).In this study, RRAM devices with a metal-insulator-metal (MIM) structure are investigated. Amorphous indium gallium zinc oxide (a-IGZO) is deposited with atmosphere pressure-plasma enhanced chemical vapor deposition (AP-PECVD). The resistivity of an a-IGZO insulator is dominated by oxygen vacancy, and the electrical characteristics of RRAM devices are crucially influenced by the insulator layer. Magnesium (Mg) is doped into an a-IGZO insulator layer to modulate the RRAM device's electrical characteristics. The results show that 1% of Mg doping makes the stability progress on devices set and read process. If more Mg is doped into a-IGZO insulator layer, Mg occupies more oxygen vacancies, and RRAM devices become more unstable and unreliable.