Multilevel Cell Operation of Gadolinium Oxide Resistive Random Access Memory Treated by Hydrogen Plasma Immersion Ion Implantation

• Main Authors: Chih Hsien Hsu, 徐志賢
• Other Authors: J. C. Wang
• Format: Others
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/65788518285506645710

碩士 === 長庚大學 === 電子工程學系 === 101 === Recently, many studies have been done in the Gd2O3 RRAM. Different top and bottom electrode material, as well as the post treatment process on the dielectric has been proposed for different switching mechanism. In this study, we attempt to improve the performance of the Gd2O3 RRAM by hydrogen plasma treatment. In this work, the characteristics of Gd2O3 resistive switching performance were improved by plasma immersion ion implantation method, in which the plasma was composed of the hydrogen gas. It is demonstrated that the appropriate hydrogen ion treatment can passivate the defects in dielectric interface layer; thus the operating voltage can be reduced owing to the much easy movement of oxygen vacancies to top junction. The resistive switching characteristic can be more stable on retention due to the defects passivation by the hydrogen. In case of the high hydrogen doping, the switching mechanism was switched from Schottky to space-charge-limited current. The high amount of the hydrogen ions can passivate the oxygen vacancies filament, and it is controllable by the operating voltage. Since this high concentration of the hydrogen, the multi-level switching can be realized by varying the operating reset voltage. The yield of multi-level switching is affected by hydrogen concentration. The device shows the optimized performance for the reduction of the operating voltage and high stable data retention by hydrogen plasma treatment for long time. Then, we observe hydrogen movement by SIMS.