Abstract
The formation energy of an oxygen vacancy and the diffusion barrier of an oxygen ion have a significant impact on the operating voltage and other parameters of resistive random access memory. In this research, n-type dopants and p-type dopants were, respectively, used to make comparative research on the formation energy of the oxygen vacancy and the diffusion barrier of the oxygen ion in orthorhombic λ-Ta2O5 taking first-principles methods. The band unfolding calculation results show that the donor level and acceptor level are, respectively, formed in the bandgap after the doping of W and Al. After the doping of Al, the formation energy of the oxygen vacancy decreases as the doping concentration increases. Instead, after the doping of W, the formation energy of the oxygen vacancy only undergoes an increase of 0.2 eV, and the diffusion barrier increases first and then decreases with the increase in the concentration of the doped W. After the doping of Al and W, the diffusion barriers of oxygen ions change within the ranges of 0.3–1.6 and 0.12–1.23 eV, respectively.
Highlights
At present, the memristor-based simulation research on the cerebral nerve is still in the initial stage
Considering that the human brain has a huge number of neurons (1011 neurons and 1015 synapses), the internal mechanism problem of resistive random access memory (RRAM) in operating voltage, if not solved, will be considerably not conducive to the simulation of the cerebral neuron and the large-scale application of the cerebral nerve network
The oxygen vacancy (VO) formation and diffusion barrier in λ-Ta2O5 were calculated by using the Density Functional Theory (DFT) based first-principles method and Vienna Ab initio Simulation Package (VASP)
Summary
The memristor-based simulation research on the cerebral nerve is still in the initial stage. Experiments show that the doping of dopants is a crucial method for adjusting and improving the electronic performance of the resistive memory layer and contributes to significant improvement in operating voltage, resistance state stability, cycle tolerance, and other properties of the device.. Kim et al demonstrated that after doping Si into the resistive memory layer Ta2O5, the RRAM shows a stable resistance state.5 They thought that it was the doping of Si that changed the jumping distance and drift speed of the oxygen ion and further improved the performance of the device. Al and W were, respectively, doped in the orthorhombic λ-Ta2O5 to study the formation energy of the oxygen vacancy and the diffusion barrier of the oxygen ion. The diffusion barrier of the oxygen ion increases with the increase in the concentration of the doped Al but increases first and gradually decreases with the increase in the concentration of the doped W
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