Metal nanocrystals synthesized with a micellar template based on a diblock copolymer for three-dimensional nonvolatile memory

Abstract

Metal nanocrystals synthesized with a micellar template were applied for three-dimensional vertical floating gate memory devices. Using a highly ordered micellar template formed with a diblock copolymer, we produced cobalt ͑Co͒ nanocrystals with a uniform size and spatial distribution on a planar surface and a sidewall surface. The hydrogen annealing effects were investigated in terms of memory performance. The fabricated vertical floating gate memory with Co nanocrystals annealed with hydrogen showed a memory window with a voltage greater than 1 V and a retention time characteristic that preserves more than 60% of the initial charge after ten years.

Nonvolatile floating gate organic memory device based on pentacene/CdSe quantum dot heterojuction

“…Second, band structure engineering methods, such as tuning band-offsets and barriers, are possible through a combination of various NCs. [9][10][11] The memory devices based on NCs, therefore, provide several merits including low power consumption, small device size, excellent stress-induced leakage current immunity, and better retention originated from the structural traits.…”

Nonvolatile organic transistor-memory devices using various thicknesses of silver nanoparticle layers

“…6 In these devices, the memory effect arises from the field effect modulation by either the spontaneous polarization that occurs in ferroelectric, or through the trapping of charges in a chargeable layer of the dielectric. 7 Usually, the charge-trapping elements in the chargeable gate dielectric are nanoparticles ͑NPs͒ of metals such as Cr, 8 Au, 6 and Ag. 9 Compared with ferroelectric polymer-based memory, devices using metal NPs as charge traps have an advantage that the trap density and distribution can be controlled by adjusting the density and location of the NPs during the NP formation process, by using ultrathin metallic films deposition or ion implantation techniques.…”

A study of the memory effects of metallic core–metal oxide shell nanocrystals by a micelle dipping technique

“…The pattern was dipped into a solution of copolymer micelles containing precursors at a rate of 20 mm min −1 , subsequently pulled out of the solution at the same rate, and then dried in air. It should be noted that Co NCs are coated uniformly onto the top surface as well as the sidewall surface in the scanning electron microscopy (SEM) images [24]. In the dip coating process, conformal and monolayered NC formation was explained by the confined convective assembly at the meniscus of the air-solution interface or direct adsorption in the bulk solution [25,26].…”

“…Recently, we demonstrated a 3D vertical floating gate memory with metal NCs as the proof-of-concept of the micelle dipping technique. The resulting cobalt (Co) NCs were synthesized by means of a reversed micellar structure based on a diblock copolymer [24]. A dipping method of synthesized micelle enabled simple and uniform metal coating for 3D arrays.…”