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Investigation of LRS dependence on the retention of HRS in CBRAM.

Xu X, Lv H, Liu H, Luo Q, Gong T, Wang M, Wang G, Zhang M, Li Y, Liu Q, Long S, Liu M - Nanoscale Res Lett (2015)

Bottom Line: The HRS degradation was found strongly dependent on the LRS: the lower the resistance of the LRS (R LRS) is, the worse HRS retention will be.The degradation of HRS is due to the filling or widening of the neck point by the diffusion of copper species from the residual filament.As the residual filament is stronger in case of the lower R LRS, the active area around the neck point for copper species diffusion is larger, resulting in higher diffusion probability and faster degradation of HRS during the temperature-accelerated retention measurement.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Nano-Fabrication and Novel Devices Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, #3 Beitucheng West Road, Chaoyang District Beijing, 100029 China.

ABSTRACT
The insufficient retention prevents the resistive random access memory from intended application, such as code storage, FPGA, encryption, and others. The retention characteristics of high resistance state (HRS) switching from different low resistance state (LRS) were investigated in a 1-kb array with one transistor and one resistor configuration. The HRS degradation was found strongly dependent on the LRS: the lower the resistance of the LRS (R LRS) is, the worse HRS retention will be. According to the quantum point contact model, the HRS corresponds to a tiny tunnel gap or neck bridge with atomic size in the filament. The degradation of HRS is due to the filling or widening of the neck point by the diffusion of copper species from the residual filament. As the residual filament is stronger in case of the lower R LRS, the active area around the neck point for copper species diffusion is larger, resulting in higher diffusion probability and faster degradation of HRS during the temperature-accelerated retention measurement.

No MeSH data available.


The schematic of resistive switching mechanism. According to the quantum point contact (QPC) model, the HRS corresponds to a tiny tunnel gap or neck bridge with atomic size in the filament.
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Fig7: The schematic of resistive switching mechanism. According to the quantum point contact (QPC) model, the HRS corresponds to a tiny tunnel gap or neck bridge with atomic size in the filament.

Mentions: Taking the failure mechanism of retention into account, more attention should be paid on the reconstruction of the conductive filament, which is responsible for the HRS failure behavior (switching to LRS). Based on our previous work [5], the reversible switching between HRS and LRS of Cu/HfO2/Pt device is in accordance with the filling and extraction of the copper species from the filament constriction, as sketched in Figure 7. Considering the HRS is in the range from 9 kΩ to 15 kΩ, which is on the level of the quantum conductance, the assumption of the HRS corresponding to a tiny tunnel gap or neck bridge with atomic size in the filament is reasonable according to the quantum point contact (QPC) model [23-25]. Due to the existence of concentration gradient, metal diffusion from the metal-rich filament to the neck point possibly happened, resulting in a gradual decrease of the HRS by the filling or widening of the neck point. In the environment with elevated temperature, the diffusion process was enhanced, leading to the acceleration of the HRS retention failure.Figure 7


Investigation of LRS dependence on the retention of HRS in CBRAM.

Xu X, Lv H, Liu H, Luo Q, Gong T, Wang M, Wang G, Zhang M, Li Y, Liu Q, Long S, Liu M - Nanoscale Res Lett (2015)

The schematic of resistive switching mechanism. According to the quantum point contact (QPC) model, the HRS corresponds to a tiny tunnel gap or neck bridge with atomic size in the filament.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385049&req=5

Fig7: The schematic of resistive switching mechanism. According to the quantum point contact (QPC) model, the HRS corresponds to a tiny tunnel gap or neck bridge with atomic size in the filament.
Mentions: Taking the failure mechanism of retention into account, more attention should be paid on the reconstruction of the conductive filament, which is responsible for the HRS failure behavior (switching to LRS). Based on our previous work [5], the reversible switching between HRS and LRS of Cu/HfO2/Pt device is in accordance with the filling and extraction of the copper species from the filament constriction, as sketched in Figure 7. Considering the HRS is in the range from 9 kΩ to 15 kΩ, which is on the level of the quantum conductance, the assumption of the HRS corresponding to a tiny tunnel gap or neck bridge with atomic size in the filament is reasonable according to the quantum point contact (QPC) model [23-25]. Due to the existence of concentration gradient, metal diffusion from the metal-rich filament to the neck point possibly happened, resulting in a gradual decrease of the HRS by the filling or widening of the neck point. In the environment with elevated temperature, the diffusion process was enhanced, leading to the acceleration of the HRS retention failure.Figure 7

Bottom Line: The HRS degradation was found strongly dependent on the LRS: the lower the resistance of the LRS (R LRS) is, the worse HRS retention will be.The degradation of HRS is due to the filling or widening of the neck point by the diffusion of copper species from the residual filament.As the residual filament is stronger in case of the lower R LRS, the active area around the neck point for copper species diffusion is larger, resulting in higher diffusion probability and faster degradation of HRS during the temperature-accelerated retention measurement.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Nano-Fabrication and Novel Devices Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, #3 Beitucheng West Road, Chaoyang District Beijing, 100029 China.

ABSTRACT
The insufficient retention prevents the resistive random access memory from intended application, such as code storage, FPGA, encryption, and others. The retention characteristics of high resistance state (HRS) switching from different low resistance state (LRS) were investigated in a 1-kb array with one transistor and one resistor configuration. The HRS degradation was found strongly dependent on the LRS: the lower the resistance of the LRS (R LRS) is, the worse HRS retention will be. According to the quantum point contact model, the HRS corresponds to a tiny tunnel gap or neck bridge with atomic size in the filament. The degradation of HRS is due to the filling or widening of the neck point by the diffusion of copper species from the residual filament. As the residual filament is stronger in case of the lower R LRS, the active area around the neck point for copper species diffusion is larger, resulting in higher diffusion probability and faster degradation of HRS during the temperature-accelerated retention measurement.

No MeSH data available.