A novel two-step method is employed, for the first time, to fabricatc nonvolatile memory devices that have metal nanoerystals. First, size-averaged Au nanocrystals are synthesized chemically; second, they are assemble...A novel two-step method is employed, for the first time, to fabricatc nonvolatile memory devices that have metal nanoerystals. First, size-averaged Au nanocrystals are synthesized chemically; second, they are assembled into memory devices by a spin-coating technique at room temperature. This attractive approach makes it possible to tailor the diameter and control the density of nanocrystals individually. In addition, processes at room temperature prevent Au diffusion, which is a main concem for the application of metal nanocrystal-based memory. The experimental results, both the morphology characterization and the electrical measurements, reveal that there is an optimum density of nanocrystal monolayer to balance between long data retention and a large hysteresis memory window. At the same time, density-controllable devices could also feed the preferential emphasis on either memory window or retention time. All these facts confirm the advantages and novelty of our two-step method.展开更多
Difficulties in the fabrication of direct interface of ferroelectric BiFeO_(3)/HfO_(2) on the gate of ferroelectric field effect transistor(FeFET)is well known.This paper reports the optimization and fabrication of fe...Difficulties in the fabrication of direct interface of ferroelectric BiFeO_(3)/HfO_(2) on the gate of ferroelectric field effect transistor(FeFET)is well known.This paper reports the optimization and fabrication of ferroelectric/dielectric(BiFeO_(3)/HfO_(2))gate stack for the FeFET applications.RF magnetron sputtering has been used for the deposition of BiFeO_(3),HfO_(2) films and their stack.X-Ray diffraction(XRD)analysis of BiFeO_(3) shows the dominant perovskite phase of(104),(110)orientation at 2θ=32°at the annealing temperature of 500℃.XRD analysis also confirms the amorphous nature of the HfO2 film at annealing temperature of 400℃,500℃ and 600℃.Multiple angle analysis shows the variation ion the refractive index between 2.98–3.0214 for BiFeO_(3) and 2.74–2.9 for the HfO2 film with the annealing temperature.Metal/Ferroelectric/Silicon(MFS),Metal/Ferroelectric/Metal(MFM),Metal/Insulator/Silicon(MIS),and Metal/Ferroelectric/Insulator/Silicon(MFIS)structures have been fabricated to obtain the electric characteristic of the ferroelectric,dielectric and their stacks.Electrical characteristics of the MFIS structure show the memory improvement from 2.7 V for MFS structure to 4.65 V for MFIS structure with 8 nm of buffer dielectric layer.This structure also shows the breakdown voltage of 40 V with data retention capacity greater than 9×10^(9)iteration cycles.展开更多
文摘A novel two-step method is employed, for the first time, to fabricatc nonvolatile memory devices that have metal nanoerystals. First, size-averaged Au nanocrystals are synthesized chemically; second, they are assembled into memory devices by a spin-coating technique at room temperature. This attractive approach makes it possible to tailor the diameter and control the density of nanocrystals individually. In addition, processes at room temperature prevent Au diffusion, which is a main concem for the application of metal nanocrystal-based memory. The experimental results, both the morphology characterization and the electrical measurements, reveal that there is an optimum density of nanocrystal monolayer to balance between long data retention and a large hysteresis memory window. At the same time, density-controllable devices could also feed the preferential emphasis on either memory window or retention time. All these facts confirm the advantages and novelty of our two-step method.
文摘Difficulties in the fabrication of direct interface of ferroelectric BiFeO_(3)/HfO_(2) on the gate of ferroelectric field effect transistor(FeFET)is well known.This paper reports the optimization and fabrication of ferroelectric/dielectric(BiFeO_(3)/HfO_(2))gate stack for the FeFET applications.RF magnetron sputtering has been used for the deposition of BiFeO_(3),HfO_(2) films and their stack.X-Ray diffraction(XRD)analysis of BiFeO_(3) shows the dominant perovskite phase of(104),(110)orientation at 2θ=32°at the annealing temperature of 500℃.XRD analysis also confirms the amorphous nature of the HfO2 film at annealing temperature of 400℃,500℃ and 600℃.Multiple angle analysis shows the variation ion the refractive index between 2.98–3.0214 for BiFeO_(3) and 2.74–2.9 for the HfO2 film with the annealing temperature.Metal/Ferroelectric/Silicon(MFS),Metal/Ferroelectric/Metal(MFM),Metal/Insulator/Silicon(MIS),and Metal/Ferroelectric/Insulator/Silicon(MFIS)structures have been fabricated to obtain the electric characteristic of the ferroelectric,dielectric and their stacks.Electrical characteristics of the MFIS structure show the memory improvement from 2.7 V for MFS structure to 4.65 V for MFIS structure with 8 nm of buffer dielectric layer.This structure also shows the breakdown voltage of 40 V with data retention capacity greater than 9×10^(9)iteration cycles.
