| 초록 |
RRAM(Resistive Random Access Memory), also known as a memristor, has a very simple MIM(Metal-Insulator-Metal) structure as compared with conventional memories. With this simple structure, RRAM is a promising memory device that is expected to satisfy high speed, high density and power efficiency. The switching operation of RRAM is known as the formation and breaking of the conductive filaments. In the case of VCM(Valence Change Mechanism), the conductive filaments consist of defects in transition metal oxides, like oxygen vacancies and metal ions. So, It is important that understanding the phenomena of formation and recombination of defects in the operating condition. In this research, A finite element simulation for the cycle of the forming-reset-set state in RRAM was developed by calculating the defect generation and recombination rate. The formation of oxygen vacancies is expressed as activation energy as a function of temperature and electric field. Electrical conductivity was expressed as a function of oxygen vacancy concentration to represent the forming-set-reset cycle in in hafnium oxide based RRAM. Additionally, the vacancy migration is modeled by thermal and drift diffusion equations. As a result, the I-V curves has represented and compared by changing variables such as the voltage rate and diffusion mechanisms. |
